In the first book for the general reader that presents the full range of scientific evidence for past and possibly future dangers, noted planetologist and impact-crater expert John S. Lewis shows us the unmistakable evidence - from space-probe flybys of the planets to the scars on our own Earth - of cataclysmic comet and asteroid impacts.

By comparing what we know about the earth's geology and paleontology with the images of the other planets and moons in our solar system, Lewis makes the strongest case yet for sudden, dramatic extinctions and assesses the risks to planet Earth. Not even Darwin was aware of the events now seen as having played such a crucial role in the evolution of life on earth.

1. Lewis tells of the dangers to our civilization, dangers in the form of near-earth asteroids, or NEAs, whose impact could destroy in an instant what it has taken humans millennia to build. Finally, he describes the searches and preventive measures being undertaken today by scientists around the globe to ward off this threat from space.