American life today is being rapidly and continuously transformed by technological progress. Kurzweil is admirably placed to give outsiders a look at the world as the technological revolutionaries see it -- and it is anything but flat. For Kurzweil, the overwhelming fact of contemporary life is the geometric acceleration of technological development. Today we are at "the knee of the curve" -- the point just before the gently rising slope of technological change becomes a vertical rise. This heralds, Kurzweil argues in terms borrowed from astrophysics, the approach of a historical "singularity": a state of affairs so radically different from everything in the past that we can know virtually nothing about it. At present rates of progress, only a few decades from now, computers that have one billion times the information processing power of the assembled brains of the entire human race will cost less than $1,000. As scientists and businesses harness this power, rates of social and technological change will accelerate further, leading to a qualitative change in the way human society works -- and, indeed, in what human life is like.