The title of this book is a bit misleading: in the first part Rutherford does indeed give a good overview of the evolutionary history of the human species ("a history of everyone who ever lived"), but thereafter he mainly gives a state of the art of genetic research in general, with everything what is involved. The first part was the main reason why I read this book, so in this review I will only go into that part.
Classic archeology has ruled the domain of earliest human history for over 150 years, since the discovery of Neanderthal bones in a cave near Düsseldorf, Germany. In the 1950s the field of action shifted to Eastern and Southern Africa, gradually drawing up a family tree of human and pre-human species, like for instance Australopithecus or Homo Erectus. This family tree had to be revised approximately every 10 years or so, following the discovery of new, older fossils or the application of new dating methods. This was sometimes accompanied by unscientific methodologies and fierce infight between archaeologists, but that is not the subject of this book.
From the 1990s onwards, genetics has put this pedigree model under intense pressure. An ever-better understanding of the DNA and especially the human genome (the entirety of the genetic code of man) made it possible to date human remains much more accurately and, above all, to establish almost unambiguous connections or distinctions between and within human species. For a while it seemed that now was offered a methodology that for once and for all could put an end to the endless disputes amongst archeologists and paleontologists.
But then it turned out that the picture was much more complicated than expected. For instance, take the study of Neandertal people, which we know disappeared about 30,000 years ago. Study of the genetic material of our Sapiens species has unequivocally shown that it also contains typical Neandertal material, on average for about 2.5%. In other words, Neandertal and Sapiens interbred (in fact in several interconnecting 'waves'), so that you can say that though Neandertal is a dead-end branch of the human species, nevertheless he lives on in us (especially Europeans and East-Asians)! The same phenomenon is established with those curious other representatives of the "homo genus": the Denisova and the Floriensis. Rutherford rightly concludes: "the ancient genomes awaiting discovery will show that the world was much more cosmopolitan in the millennia before we became the last representative of the homo genus". And: "It's now clearer than ever. that the old, simplistic view of how we became what we are is simply not correct. Gone are the days of neatly branched trees, of the bent monkey walking upright step by step”.
Nice, but what did surprise me is that this spectacular evolution in genetic research is also subject to its own limitations. For example, almost all genetic research is focussed on the analysis of 'mitrochondrial DNA', that's a part of the genetic code that is situated outside of the cell nucleus, and it is easier to 'read' than the very long DNA-strings within the nucleus. Now this 'mitrochondrial DNA' is only transmitted to a next generation by the mother (the father has his own unique 'parcel', the well-known Y-chromosome). Limiting research to this part has the advantage of enabling a much faster analysis and establishing clear lines of connections and distinctions. But nevertheless, can we really be sure that this is a reliable method that gives us the whole picture? Of course, I'm a layman in these affairs, but once again it seems science is taking the path of segmentation, risking reductionism.
Another limitation: apparantly it is not possible to extract DNA from species older than 100-50,000 years: the DNA in the fossil remains has almost always completely disintegrated, due to heat and moisture. The oldest complete genome of a sapiens is only 45,000 years old (at least it was the year this book was published, in 2016). In other words: for the time being, genetic research does not tell us everything about the earliest history of mankind, and especially about its predecessors, the australopithicus or the homo erectus of which we have found lots of fossils, not useful to genetic research. Only indirectly some data can be retrieved, by specifically looking at the quantity and diversity of mutations detectable within the 'modern' DNA, and establishing how many generations ago a certain mutation took root in a certain population or species.
So, up until now, most of the gains of genetic research are within the history of Homo Sapiens itself. For instance, genetics has been able to map the migration waves of the Sapiens in a much better and more reliable way than classic archeology. But once again the answers are not completely unambiguous: genetic research confirms that agriculture certainly came to Europe via migration flows (a first wave from about 9,700-7,000 BP, and a second much larger one after 5,000 BP), but that too was accompanied by a considerable mixing with the local hunter-gatherer population, making it difficult to answer the classic question whether hunter-gatherers were expelled and annihilated by farmers, or adopted farming methods and were integrated in the farming population.
Rutherford makes it clear that genetic research does provide us with a lot of new insights, but at the same time confronts us with a lot of new questions. Almost every door that is opened leads to new branching paths. In other words, genetic research does not provide all the answers, although Rutherford is convinced that science will continue to make progress and unravel more and more mysteries. Only time can tell. This is a nice introduction to an exciting new domain of studies, but beware: things are evolving so fast in this field, that a book such as this quickly can become outdated.