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Nexus: Small Worlds and the Groundbreaking Science of Networks
As Chaos explained the science of disorder, Nexus reveals the new science of connection and the odd logic of six degrees of separation. "If you ever wanted to know how many links connect you and the Pope, or why when the U.S. Federal Reserve Bank sneezes the global economy catches cold, read this book," writes John L. Casti (Santa Fe Institute). This "cogent and engaging" ( Nature ) work presents the fundamental principles of the emerging field of "small-worlds" theory―the idea that a hidden pattern is the key to how networks interact and exchange information, whether that network is the information highway or the firing of neurons in the brain. Mathematicians, physicists, computer scientists, and social scientists are working to decipher this complex organizational system, for it may yield a blueprint of dynamic interactions within our physical as well as social worlds.
Highlighting groundbreaking research behind network theory, "Mark Buchanan's graceful, lucid, nontechnical and entertaining prose" (Mark Granovetter) documents the mounting support among various disciplines for the small-worlds idea and demonstrates its practical applications to diverse problems―from the volatile global economy or the Human Genome Project to the spread of infectious disease or ecological damage. Nexus is an exciting introduction to the hidden geometry that weaves our lives so inextricably together.
Highlighting groundbreaking research behind network theory, "Mark Buchanan's graceful, lucid, nontechnical and entertaining prose" (Mark Granovetter) documents the mounting support among various disciplines for the small-worlds idea and demonstrates its practical applications to diverse problems―from the volatile global economy or the Human Genome Project to the spread of infectious disease or ecological damage. Nexus is an exciting introduction to the hidden geometry that weaves our lives so inextricably together.
236 pages, Paperback
First published January 1, 2002
34 people are currently reading
816 people want to read
About the author
Mark Buchanan
7 books58 followersA physicist and author based in Europe writing mostly about science - physics, mathematics, social science and biology.
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Displaying 1 - 30 of 34 reviews
April 8, 2015
I liked this book... it presented a lot of interesting material, even if it did not show that all the material was related--if there was a basic theme or similarity between all the examples mentioned, I would say that it's that networks sometimes have a power-law distribution of vertex degrees. I'm not entirely impressed by this idea (perhaps it was more novel around the time of the book's publication?). This inspired me to read another book, Mark Newman's Networks: An Introduction, which had the informative and well researched statement:
"Power laws turn up in a wide variety of places, not just in networks. They are found in the sizes of city populations, earthquakes, moon craters, solar flares, computer files, and wars; in the frequency of use of words in human languages, the frequency of occurrence of personal names in most cultures, the numbers of papers scientists write, and the number of hits on web pages; in the sales of books, music recordings, and almost every other branded commodity; and in the numbers of species in biological taxa." [see book for extensive references]
I also think some of the author's references were dated and off-putting. Referencing Karl Popper (with 'you can't predict future history') as someone with any authority on the issue completely and immediately undercuts the message of the book--that group dynamics can sometimes be determined by the network of the group (which is explicitly to say that you could predict group dynamics of, say, human societies (future history), by analyzing the network structure and information propagation across it). Referencing Monica Lewinsky seemed immature... perhaps at publication this joke would have elicited a groan, but now it just reads as petty and disrespectful. I guess that says that this book was intended to be read as current pop science, and acknowledges that it will have less and less value as it ages. Also there was a conflation of several different meanings and uses of the word 'network', which don't all relate to the newly discovered math of graphical networks. Scientifically imprecise.
For me the main appeal of this book is the subject, and the novelty and newfound excitement about it that is evident in the author's approach. 'Awe-full' might be a good portmanteau to describe it (though I'm sure I'd find a more suitable word if I were audibly speaking this review;). I don't think this writing has aged well, but I don't think it presumed to be able to either. I'd be excited to read a newly-revised update.
"Power laws turn up in a wide variety of places, not just in networks. They are found in the sizes of city populations, earthquakes, moon craters, solar flares, computer files, and wars; in the frequency of use of words in human languages, the frequency of occurrence of personal names in most cultures, the numbers of papers scientists write, and the number of hits on web pages; in the sales of books, music recordings, and almost every other branded commodity; and in the numbers of species in biological taxa." [see book for extensive references]
I also think some of the author's references were dated and off-putting. Referencing Karl Popper (with 'you can't predict future history') as someone with any authority on the issue completely and immediately undercuts the message of the book--that group dynamics can sometimes be determined by the network of the group (which is explicitly to say that you could predict group dynamics of, say, human societies (future history), by analyzing the network structure and information propagation across it). Referencing Monica Lewinsky seemed immature... perhaps at publication this joke would have elicited a groan, but now it just reads as petty and disrespectful. I guess that says that this book was intended to be read as current pop science, and acknowledges that it will have less and less value as it ages. Also there was a conflation of several different meanings and uses of the word 'network', which don't all relate to the newly discovered math of graphical networks. Scientifically imprecise.
For me the main appeal of this book is the subject, and the novelty and newfound excitement about it that is evident in the author's approach. 'Awe-full' might be a good portmanteau to describe it (though I'm sure I'd find a more suitable word if I were audibly speaking this review;). I don't think this writing has aged well, but I don't think it presumed to be able to either. I'd be excited to read a newly-revised update.
January 1, 2017
The best book I read in 2016. Also the last book I read in 2016.
If you get off on mental models, interdisciplinary approaches, complex systems, and care about applying them to phenomena such as wealth, disease, friendship, and social good, this book will absolutely blow your mind.
Probably the most motivating preface I've ever read.
Occasionally, the author says something a little too grandiose or tells a story where there are other compelling explanations, but he's generally good at staying in his lane and sticking to the math and the research.
Excited to read the rest of his books.
If you get off on mental models, interdisciplinary approaches, complex systems, and care about applying them to phenomena such as wealth, disease, friendship, and social good, this book will absolutely blow your mind.
Probably the most motivating preface I've ever read.
Occasionally, the author says something a little too grandiose or tells a story where there are other compelling explanations, but he's generally good at staying in his lane and sticking to the math and the research.
Excited to read the rest of his books.
January 8, 2009
The first half was a bad summary of 'Linked' and the rest had far too much generalization, not nearly enough specifics.
July 11, 2010
Fascinating read about small-world networks. Really high-level, pop science, and there's a bit of overlap with "Ubiquity" (vis-a-vis power laws), but good food for thought nevertheless. I do wish he'd bothered to sum up the take-aways a bit more succinctly; seems as though he was shying away from making any real strong claims or predictions.
February 6, 2014
Completely fascinating. The world is both way more complex and much simpler than I thought. If you want to know what firefies in New Guinea have to do with the spread of AIDS, read this.
March 1, 2016
Admirably researched overview of small world networks.
April 19, 2019
Nexus is a nice introduction to complexity, tipping points, networks, and small worlds. Basically an examination of the general pattern that shows up in almost everything. This network of small worlds consists of clumps which have weak links to others making a networking pattern that goes through the whole, whatever that whole may be. Buchanan relates some of the development of the idea and how it has been employed, exploring many different areas including ecology, behavior, economics, the structure of ice, and epidemiology. He concludes with a general section on the insights gained and projects into the future. Although there is a sense in which these ideas are not new, they have not been so well articulated or understood. The book offers some insights that will help you get started.
May 4, 2016
Fascinating and very readable
I loved the wide range of examples of network theory - everything from HIV transmission to behavioral economics to social systems and the Internet. This has inspired me to learn more about systems theory.
I loved the wide range of examples of network theory - everything from HIV transmission to behavioral economics to social systems and the Internet. This has inspired me to learn more about systems theory.
June 20, 2017
This book is an interesting journey through complexity theory primarily focused on small world networks.
It turns common sense on its head. An example is the Japanese fishermen who think that removing whales from the ecosystem will result in more fish. Seems to make sense. But because of all the complex interconnections of the worlds oceans the fish population might decline. Perhaps the whales benefit the food(smaller fish) of the fish they eat. Perhaps whales are less voracious than alternative predators, who without the whales, are free to expand in population. The point is complex phenomenon do not have clear causal links.
It turns common sense on its head. An example is the Japanese fishermen who think that removing whales from the ecosystem will result in more fish. Seems to make sense. But because of all the complex interconnections of the worlds oceans the fish population might decline. Perhaps the whales benefit the food(smaller fish) of the fish they eat. Perhaps whales are less voracious than alternative predators, who without the whales, are free to expand in population. The point is complex phenomenon do not have clear causal links.
July 10, 2018
I first came across the theory of Networks a while ago, and naturally didn't quite understand the hype about it, it sounded like a miraculous lens through which everything (almost) makes sense. Just as intriguing as the golden ratio being EVERYWHERE... A bit alienating...
This book doesn't contain a thorough explanation with equations and graphs and so, and so .... (However I would've loved to see the Fat tail distribution curve next to the results), it is rather a long introduction to how networks theory is shaping our sciences.. and offering new exploration angles ..
This book doesn't contain a thorough explanation with equations and graphs and so, and so .... (However I would've loved to see the Fat tail distribution curve next to the results), it is rather a long introduction to how networks theory is shaping our sciences.. and offering new exploration angles ..
June 24, 2020
One of the best introductions to networks
November 19, 2020
In pratica è una sorta di Caos Pt.II, un continuo al libro di James Gleick. Interessante, come al solito Buchanan arriva per primo nella divulgazione delle nuove frontiere della Fisica (Applicata)
August 1, 2012
L'argomento del libro sono quelle che l'autore chiama "reti piccolo mondo": detta così non dice nulla, ma probabilmente se cito la teoria più comune ad esse legata, quella dei sei gradi di separazione, forse è più chiaro.Per chi non lo sapesse, la teoria dei sei gradi di separazione dice che ogni essere umano è collegato ad un altro da al massimo sei "strette di mano", ovvero collegamenti anche lievi tra persone che permetterebbero di unirne una ad un'altra: questo, ripeto, per ogni essere vivente sul pianeta.Leggenda metropolitana? Forse, però effettivamente Buchanan porta avanti uno studio sull'argomento e su come queste relazioni tra elementi, queste "reti piccolo mondo", siano in realtà molto più diffuse di quanto crediamo, sia nell'ambito naturale (ad esempio i neuroni) sia in quello artificiale (internet stessa).Certo, anche l'autore afferma che forse i sei gradi sono un po' riduttivi, ma tendenzialmente 10 è un numero assolutamente credibile: magari molti di questi collegamenti non li conosciamo perché si basano su legami deboli, ma tendenzialmente esistono per tutti; d'altronde a quanti di noi è capitato di scoprire conoscenze in comune con gente appena incontrata? E' solo uno degli esempi possibili.Per fare un esempio più concreto: io e Madonna siamo separati da soli 4 gradi... come?Beh, io ho partecipato come pubblico a Passaparola anni fa (grado 1).A passaparola è stata ospite più di una volta Romina Mondello (grado 2).Romina Mondello è stata fidanzata per un periodo con Raul Bova (grado 3).Raul Bova ha fatto una pubblicità con Madonna (grado 4).Intrigante, secondo me :)PS: Se poi siete ancora curiosi e volete provare a collegare gli attori (ad esempio) tra di loro, provate all'indirizzo http://www.cs.virginia.edu/oracle/ dove potrete scoprire i gradi di separazione tra Kevin Bacon e qualunqua altro attore (Moana e Kevin sono separati da soli 3 gradi, vi rendete conto?) oppure (al link "Star Links") potete scegliere voi quali personaggi mettere in relazione.
July 27, 2014
Che cosa accomuna i rapporti sociali, l'economia, la struttura del World Wide Web e la diffusione delle malattie?
Il saggio divulgativo di Mark Buchanan, fisico teorico, cerca di rispondere a queste domande. Con disinvoltura e con un linguaggio semplice e accattivante espone i vari tipi di rete esistenti. Una rete fortemente aggregata ma priva di contatti "casuali" sembrerebbe incrementare la fiducia dei vari membri e di contro scoraggiare la diffusione delle idee o "memi"; una rete casuale invece, nella quale i vari membri intrattengono rapporti "a casaccio" non vincolati da contiguità spaziale,
non sembrerebbe rispecchiare una situazione realistica. Infine vi sono delle reti che riassumono tutte le caratteristiche delle due precedenti: sono le reti "piccolo mondo", reti fortemente aggregate e aventi anche dei "legami deboli" definiti così dal sociologo americano Granovetter; questi legami permetterebbero la coesione di tutta la rete mondiale e di gruppi umani fortemente aggregati che altrimenti resterebbero isolati. In una rete sociale, per esempio, pochi individui al mondo (chiamati hubs) sembrerebbero svolgere questa funzione coesiva: la loro scomparsa invece potrebbe sortire degli effetti disastrosi sull'intera rete. Buchanan analizza una particolarità di questo tipo di rete: attraverso soli sei passaggi (una catena comprendente gli amici degli amici degli amici degli amici degli amici degli amici) permetterebbe
a qualsiasi uomo di contattare il Presidente degli Stati Uniti: ogni individuo è separato da soli sei gradi da qualsiasi altro abitante sulla faccia della Terra. Attraverso il gusto del paradosso Buchanan arriva a una conclusione: il mondo apparentemente dominato dal caos sembra in realtà vincolato da leggi e configurazioni topologiche precise, che non sarebbero frutto della capricciosa volontà individuale, ma quasi il risultato di un'anima universale.
Il saggio divulgativo di Mark Buchanan, fisico teorico, cerca di rispondere a queste domande. Con disinvoltura e con un linguaggio semplice e accattivante espone i vari tipi di rete esistenti. Una rete fortemente aggregata ma priva di contatti "casuali" sembrerebbe incrementare la fiducia dei vari membri e di contro scoraggiare la diffusione delle idee o "memi"; una rete casuale invece, nella quale i vari membri intrattengono rapporti "a casaccio" non vincolati da contiguità spaziale,
non sembrerebbe rispecchiare una situazione realistica. Infine vi sono delle reti che riassumono tutte le caratteristiche delle due precedenti: sono le reti "piccolo mondo", reti fortemente aggregate e aventi anche dei "legami deboli" definiti così dal sociologo americano Granovetter; questi legami permetterebbero la coesione di tutta la rete mondiale e di gruppi umani fortemente aggregati che altrimenti resterebbero isolati. In una rete sociale, per esempio, pochi individui al mondo (chiamati hubs) sembrerebbero svolgere questa funzione coesiva: la loro scomparsa invece potrebbe sortire degli effetti disastrosi sull'intera rete. Buchanan analizza una particolarità di questo tipo di rete: attraverso soli sei passaggi (una catena comprendente gli amici degli amici degli amici degli amici degli amici degli amici) permetterebbe
a qualsiasi uomo di contattare il Presidente degli Stati Uniti: ogni individuo è separato da soli sei gradi da qualsiasi altro abitante sulla faccia della Terra. Attraverso il gusto del paradosso Buchanan arriva a una conclusione: il mondo apparentemente dominato dal caos sembra in realtà vincolato da leggi e configurazioni topologiche precise, che non sarebbero frutto della capricciosa volontà individuale, ma quasi il risultato di un'anima universale.
March 1, 2010
In the genre of presenting a field of scientific ideas to a general audience, ala Malcolm Gladwell. The book is engaging, but the style isn't as engaging as Gladwell's.
The subject is network theory. My own perspective on networks is from a very sociological and anthropological view. The reader will find some of that here, but the emphasis is more on the formal organizational properties of networks, particularly on the "small world" and "power law" networks that exhibit a combination of clustering and rather short average path distances, why such networks are common in a variety of settings as diverse as social networks, neural networks, transportation and electric power grid networks, and ecological networks. A good read for someone interested in understanding the logic of organization inherent in network structures and how network properties shape those embedded in them.
As some other reviewers have mentioned, readers might find it more useful to go directly to Barabasi's Linked or Duncan Watts' Small Worlds as much of the first part of Nexus is covered in greater depth in those two works.
The subject is network theory. My own perspective on networks is from a very sociological and anthropological view. The reader will find some of that here, but the emphasis is more on the formal organizational properties of networks, particularly on the "small world" and "power law" networks that exhibit a combination of clustering and rather short average path distances, why such networks are common in a variety of settings as diverse as social networks, neural networks, transportation and electric power grid networks, and ecological networks. A good read for someone interested in understanding the logic of organization inherent in network structures and how network properties shape those embedded in them.
As some other reviewers have mentioned, readers might find it more useful to go directly to Barabasi's Linked or Duncan Watts' Small Worlds as much of the first part of Nexus is covered in greater depth in those two works.
May 11, 2016
This book is a brief overview of network theory. Buchanan explains to the layman the difference between egalitarian networks (where networks grow organically with the same number of links) and aristocratic networks (where networks grow through a few specific nodes) and how they relate to food chains, extinction, the Internet, social networks, epidemics, economics, peer-reviewed scientific papers, social segregation, and the famous "six degrees of separation." Buchanan readily admits that this new science is not reductionist based, but attempts to look at the larger web to truly understand the nature of some networks. What is interesting to me is that physicists through this theory can help explain the nature of money, microbiology, social stratification, or virtually any other discipline. Occasionally, Buchanan condescendingly views long held theories as childish or unimaginative, much to his discredit. This book is also a little dated and relies on a lot of European scientific studies. Nevertheless, who knew that the "Oracle of Bacon" would provide such a new and startling field of study that could finally explain vast gaps in so many disciplines?
December 22, 2007
This book is awesome. Ever wondered how you could possibly be connected to a farmer in Brazil or a Russian ice fisherman? Do you find it odd when you run in to random people when you're on vacation in NYC? It lays out the theories (like Granovetter's Strength of Weak Ties) and experiments (crazy ol' Erdos) that lead to the theory of small world networks. It's written by a journalist, so like the Shilts book, it reads quick, fun, and interesting. The Six Degrees of Kevin Bacon is based on small world network theory. This may seem totally uninteresting to many, but will be a basis of my dissertation work looking at word-of-mouth and how health information is spread through small world networks. I suggest reading this book to everyone. It's really really fun!
February 15, 2009
Have you ever wondered what the hell Kevin Bacon has to do with the 6 degrees of separation idea? Have you ever looked at river beds on Google Earth and marveled at how much they look like fractal patterns?
Hidden patterns that connect you, yes you to the Pope. There are connections to to everything conceivable. The emerging field of "small worlds" theory gives us a glimpse of how hidden patterns interact and exchange information, and how everything here and in the cosmos can be broken down into a single as yet unidentified unifying mathematical equation.
Hidden patterns that connect you, yes you to the Pope. There are connections to to everything conceivable. The emerging field of "small worlds" theory gives us a glimpse of how hidden patterns interact and exchange information, and how everything here and in the cosmos can be broken down into a single as yet unidentified unifying mathematical equation.
April 16, 2012
Pretty interesting book. Albeit, a little complex in between, the author certainly does drive home the point with a lot of interesting examples. However, the examples based on the "laboratory" experiments do seem a little waste due to the strict control of conditions and removal of many factors which would in real world situations have far-reaching effects on the outcomes. His reference to Malcolm Gladwell's Tipping Point was also a refresher and made it clear that the author had done his homework well. A good read, but a better applied philosophy.
October 8, 2009
It really is a small world.
I didn't read the whole book. What got my attention was the idea that the whole 6-degrees system works because of just 4 random social links per tightly-linked groups of 50 (I imagine a roving band of stone age humans traipsing across Earth in search of a better place to hang out and breathe) .. and then something clicked in my mind .. what if most links could be de-randomised. What if ...
I didn't read the whole book. What got my attention was the idea that the whole 6-degrees system works because of just 4 random social links per tightly-linked groups of 50 (I imagine a roving band of stone age humans traipsing across Earth in search of a better place to hang out and breathe) .. and then something clicked in my mind .. what if most links could be de-randomised. What if ...
August 15, 2013
Having stumbled through a graph theory course in college, I can say the author puts a pretty good popular face on largely painful, frustrated memories.
Translating arcane statistical physics and network theory into implications about the efficacy of various schemes for fighting AIDS made for interesting reading. And of course, to be filed away for those cocktail conversations about why the study of basic science, math, should be funded.
July 12, 2008
"Nexus" covers much the same network-science ground as Barabasi's "Linked" -- Milgram's "six degrees" experiments, the spread of HIV, Granovetter's weak ties -- that reading both is somewhat redundant. That said, Buchanan digs deeper into cumulative advantage (i.e, the rich get richer), an understanding that, IMHO, explains a whole lot.
August 12, 2008
This is a great study of WHY the six degrees of separation theory is not just a theory, but a plausible explanation of how our world works. It's fascinating, but the math bits, get a bit dry and complicated. Again, best as a skimmer... but still worth going through a bit nonetheless if you liked Undercover Economist. But not nearly as entertaining as Tipping Point style.
August 2, 2011
Overall interesting. Good readability for a science book. I find the style and content similar to Malcolm Gladwell (The Tipping Point and Blink).
It's all about why there are only 6 degrees of separation from Kevin Bacon and how that applies to societal wealth, river flows, Internet infrastructure, and disease pandemics.
It's all about why there are only 6 degrees of separation from Kevin Bacon and how that applies to societal wealth, river flows, Internet infrastructure, and disease pandemics.
September 14, 2008
The basic idea on this book is understanding how important network is own our society. Yhe writer shares the theory of six degree of separation. How everyone is separated to each other just knowing 6 people or less.
March 30, 2012
Great explanation of complex mathematical phenomenon relating to networks that help explain many things from communities to river systems. I highly recommend it to anyone who likes science for the non-scientist-educated-person.
June 25, 2008
Buchanan basically reviews the literature to show how physics is beginning to explain how diseases spread and how the economy always makes the rich get richer. Fascinating.
February 26, 2011
interesting book that quite impressibly demonstrates how everything is connected with everything.
good, accessible, and educating read!
good, accessible, and educating read!
April 11, 2016
Really good. Kind of the "Freakonomics" of social network theory.
September 11, 2025
Really good. Kind of the "Freakonomics" of social network theory.
Displaying 1 - 30 of 34 reviews