During the seventeen years she worked in the US Fish and Wildlife Service, Rachel Carson learned about the problems of pesticides. Undaunted by the chemical companies' hostility and by the public's high enthusiasm for pesticides, she wrote a book called Silent Spring, which caused a major shift in public consciousness about the environment.
The following is a paraphrase of an excerpt from the letter Rachel Carson sent to Reader's Digest in 1945 offering to write an article about the dangers of DDT:
The experiments at Patuxent have been planned to show what effects DDT may have if applied to
wide areas: how it will affect insects, waterfowl, or birds that depend on insect food, and whether the use of DDT may upset the whole delicate balance of nature * (Stwertka, p. 37).