They appeared on earth 400 million years ago, long before the first reptile, bird or mammal. They make up about 75 percent of the 1.2 million currently known species of animal. As many as 30,000 of them coexist and interact in one square yard of the top inch of a forest's soil. The success of insects is the story told in this work. Gilbert Waldbauer pursues this question from hot springs and Himilayan slopes to roadsides and forests, scrutinizing insect life in its many manifestation.