A Matter for Men — David Gerrold

THE WAR AGAINST THE CHTORR

With the human population ravaged by a series of devastating plagues, the alien Chtorr arrive on earth to begin the final phase of their invasion. Even as many on earth deny their existence, the giant wormlike carnivores prepare the world for the ultimate violation--a total transformation into a monstrous Chtorran ecosystem where human beings have no place...except as food.

As a young research student, Jim McCarthy was sent to study the extraterrestrial worms and to make first contact. Now, as a soldier in the Special Forces, his sole purpose is to hunt down and kill the aliens--and save the fragile human species from extinction.