Excerpt from Radical Evolution by Joel Garreau, plus links to reviews, author biography & more

It's been a long time since the earth has seen more than one kind of human walking around at the same time. About 25,000 years if you believe that Cro-Magnons were critters significantly different from "behaviorally modern" Homo sapiens. About 50,000 years if your reading of the fossil evidence suggests you have to go back to the Neanderthals with their beetle brows and big teeth to discover an upright ape really different from us. The challenge of this book is that we may be heading into such a period again, in which we will start seeing creatures walk the Earth who are enhanced beyond recognition as traditional members of our species. We are beginning to see the outlines of such a divergence now. In 2003, President Bush signed a $3.7 billion bill to fund research that could lead to medical robots traveling the human bloodstream to gobble up cancer or fat cells, for those who can afford the procedures. At the University of Pennsylvania, male mouse cells are being transformed into egg cells. If this science works in humans, it opens the way for two gay males to make a baby, each contributing 50 percent of his genetic material–and blurring the standard model of parenthood.

As you get further into these pages, you will meet real people with real names and faces working today toward just such modifications of what it means to be human. The powerful driver of this roller coaster is the continuing curve of exponential change. Evolution is accelerating so fast, some claim, that the last twenty years are not a guide to the next twenty years, but at best a guide to the next eight. By the same arithmetic, the last fifty years perhaps are not a guide to the next fifty years. They are, some guess, a guide to the next fourteen. As I type this, the evening news is airing yet another report describing some advance as "science fiction coming close to reality." Remember that phrase. You're going to be hearing it a lot in the coming years. When that occurs, I would like you to remember this book.

At least three alternative futures flow from this accelerated change, according to knowledgeable people who have thought about all this, as you will see in ensuing chapters. The first scenario is one in which, in the next two generations, humanity is rapidly replaced by something far more grand than its motley self. Call that The Heaven Scenario. The second is the one in which in the next 25 years or so, humanity meets a catastrophic end. Call it The Hell Scenario. You will find chapters on each, because both scenarios are plausible, and either would lead to the end of human history as we know it, and soon. The third scenario is more complex. It is the one we might call The Prevail Scenario. In this scenario, the future is not predetermined. It is full of hiccups and reverses and loops, all of which are the product of human beings coming to grips with their own destinies. In this world, our values can and do shape our future. We do have choices; we are not at the mercy of large forces. We can prevail.

I approach these three scenarios with an open mind, but critically. I try not to advocate any of them–I report them. Nor am I aiming this book at the 90-percent-male alpha-geek population who devours Wired magazine, that talisman of the digitally hip. If they find merit in my work, I am honored. But I hope for a broader audience. I try to speak to some very bright people I know–my mother, my daughters–who care far more about humans than they do machines. Me too.

Excerpted from Radical Evolution by Joel Garreau Copyright © 2005 by Joel Garreau. Excerpted by permission of Doubleday, a division of Random House, Inc. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.