Silent Spring

　Silent Spring is written by Rachel Carson, an American marine biologist(海洋生物学家). In the book, she describes what humans might face in a world without birds, bees or butterflies. She warned people of the danger of using pesticides(农药), as it may lead to a spring without birdsong.

　The book is very scientific. It gives an in-depth look on how pesticides get into the food chain(食物链) and then pollute the environment and harm human health. It led to environmental protection movements(运动) worldwide. And it also saw the birth of many environmental protection organizations. They made the United Nations decide to hold the Human Environment Conference in Stockholm in 1972.