In 1963 an important national symbol almost became extinct. According to the U.S. Fish and Wildlife Service, only 417 pairs of bald eagles nested in the continental United States that year. Eagle eggs cracked open easily because the parents ate prey containing the chemical dichlorodiphenyl trichloroethane (DDT), a pesticide widely used to kill insects that fed on field crops. In 1972, the use of DDT was banned in the United States, and the outcome was remarkable. By 1995, the bald eagle totaled 4,712 pairs and was no longer on the endangered species list. Credit for the eagle's comeback is often given to the effects of one book: Silent Spring (1962), by Rachel Louise Carson. This quiet, determined woman not only helped save the eagle, but also raised the public's awareness of the damaging effects of pesticide pollution...