A major premise of the Kurzweil book is that technological change accelerates exponentially, and that even the exponentials are accelerating. Each epoch builds on the last. Epochs are getting shorter.
Kurzweil focuses on complexity, noting that evolution produces increasing order, and that technology can extend evolution by building ever-more-efficiently on this order. Very quick feedback loops are all around us, pushing the rate of technological change along and producing faster and smaller devices. Meanwhile, biological evolution continues, but at such a slow rate that it hardly matters.
He boldly predicts that computers as we know them will disappear by the end of this decade, to be replaced by virtual reality environments. No more offices by 2020. He suggests it's time to invest in tiny sensors and natural language search engines that can topple Google.
He's probably right, although it may take more than 20 years for all of this to happen.
[Really -- why can't we ask a question of all of this online information and get back something meaningful? Search engines right now are great at finding things we are already confident exist, but not so great at helping us put information in order so that we can increase our own intelligences. Training in pattern recognition -- that's what we need search engines for.]
Even if he's only half right (or even less than half right), Kurzweil's work suggests that it's a good time to be alive and interested in the effect of technology on human beings.