It's been a few weeks since I read it and the details are already fuzzy - he provides a lot of examples and detailed explanations to back up his thesis. I skimmed through several paragraphs in a couple of the chapters because it gets pretty boring. But Kurzweil's main predictions are at times mind blowing, scary, difficult to buy into.

Kurzweil - who supposedly is a respected inventor and futurist who's made accurate predictions in the past - claims that through technological advances in Gene Therapy, Nanotechnoloy, and Robotics (GNR), humans and machines will become indistinguishable within the next 30-40 years. He names this merging of humans and machines "the Singularity."

Kurzweil bases his predictions on ideas like Moore's law, and other rates of advancement in various technological fields. He offers all kinds of numbers and figures to back up his ideas. As interesting as his predictions are, the book is hard to wade through. And it's more than a little creepy to hear the human body referred to as Human Body 2.0. I gave it four stars because some of the ideas really did blow my mind and got me thinking pretty deeply about the nature and destiny of humanity, etc. But I think Kurzweil is far too optimistic. Not just about the technological predictions, but in his belief that humans will go along with human-machine integration. He has admittedly seen the Matrix and Terminator but doesn't believe the potential dark side of AI will dominate. Although, he does spend a chapter at the end answering fears and criticism of his ideas. I get the impression he's just another man obsessed with immortality and overzealous about science and technology being the answer.

Some of his predictions (from a list on wikipedia http://en.wikipedia.org/wiki/Predicti..., now you don't need to read the book:

2018
-1013 bits of computer memory--roughly the equivalent of the memory space in a single human brain--will cost $1000.

2020
-One personal computer will have the same processing power as a human brain.

2020s
-Computers less than 100 nm in size will be possible.
-Highly advanced medical nanobots will perform detailed brainscans on live patients.
-Accurate computer simulations of the entire human brain will exist due to these hyperaccurate brainscans, and the workings of the brain will be understood.
-By the later part of this decade, virtual reality will be so high-quality that it will be indistinguishable from real reality.
-The threat posed by genetically engineered pathogens permanently dissipates by the end of this decade as medical nanobots--infinitely more durable, intelligent and capable than any microorganism--become sufficiently advanced.
-A computer passes the Turing test by the last year of the decade (2029), meaning that it is a Strong AI and can think like a human (though the first A.I. is likely to be the equivalent of a very stupid human). This first A.I. is built around a computer simulation of a human brain, which was made possible by previous, nanotech-guided brainscanning.

2030s
-Mind uploading becomes possible.
-Nanomachines could be directly inserted into the brain and could interact with brain cells to totally control incoming and outgoing signals. As a result, truly full-immersion virtual reality could be generated without the need for any external equipment. Afferent nerve pathways could be blocked, totally canceling out the "real" world and leaving the user with only the desired virtual experience.
-Recreational uses aside, nanomachines in peoples' brains will allow them to greatly expand their cognitive, memory and sensory capabilities, to directly interface with computers, and to "telepathically" communicate with other, similarly augmented humans via wireless networks.
-The same nanotechnology should also allow people to alter the neural connections within their brains, changing the underlying basis for the person's intelligence, memories and personality.
-Human body 2.0 (as Kurzweil calls it) is incrementally accumulated into this decade. It consists of a nanotechnological system of nourishment and circulation--obsolescing many internal organs--and an improved skeleton.

2040s
-Human body 3.0 is gradually implemented during this decade. It lacks a fixed, corporeal form and can alter its shape and external appearance at will via foglet-like nanotechnology (similar to the T-1000 from Terminator 2).
-People spend most of their time in full-immersion virtual reality (Kurzweil has cited The Matrix as a good example of what the advanced virtual worlds will be like, without the dystopian twist).

2045: The Singularity
-$1000 buys a computer a billion times more intelligent than every human combined. This means that average and even low-end computers are vastly smarter than even highly intelligent, unenhanced humans.
-The technological singularity occurs as artificial intelligences surpass human beings as the smartest and most capable life forms on the Earth. Technological development is taken over by the machines, who can think, act and communicate so quickly that normal humans cannot even comprehend what is going on. The machines enter into a "runaway reaction" of self-improvement cycles, with each new generation of A.I.s appearing faster and faster. From this point onwards, technological advancement is explosive, under the control of the machines, and thus cannot be accurately predicted.
-The Singularity is an extremely disruptive, world-altering event that forever changes the course of human history. The extermination of humanity by violent machines is unlikely (though not impossible) because sharp distinctions between man and machine will no longer exist thanks to the existence of cybernetically enhanced humans and uploaded humans.

Post-2045: "Waking up" the Universe

* The physical bottom limit to how small computer transistors (or other equivalent, albeit more effective components, such as memristors integrated into Crossbar latches) can be shrunk is reached. From this moment onwards, computers can only be made more powerful if they are made larger in size.
* Because of this, A.I.s convert more and more of the Earth's matter into engineered, computational substrate capable of supporting more A.I.s. until the whole Earth is one, gigantic computer.
* At this point, the only possible way to increase the intelligence of the machines any farther is to begin converting all of the matter in the universe into similar massive computers. A.I.s radiate out into space in all directions from the Earth, breaking down whole planets, moons and meteoroids and reassembling them into giant computers. This, in effect, "wakes up" the universe as all the inanimate "dumb" matter (rocks, dust, gases, etc.) is converted into structured matter capable of supporting life (albeit synthetic life).
* Kurzweil predicts that machines might have the ability to make planet-sized computers by 2099, which underscores how enormously technology will advance after the Singularity.
* The process of "waking up" the universe could be complete as early as 2199, or might take billions of years depending on whether or not machines could figure out a way to circumvent the speed of light for the purposes of space travel.
* With the entire universe made into a giant, highly efficient supercomputer, AI and human hybrids (so integrated that, in truth it is a new category of "life") would have both supreme intelligence and physical control over the universe. Kurzweil suggests that this would open up all sorts of new possibilities, including abrogation of the laws of Physics, interdimensional travel, and a possible infinite extension of existence (true immortality).