Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Paul Ralph Ehrlich (born 29 May 1932) is an American biologist and educator who is the Bing Professor of Population Studies in the department of Biological Sciences at Stanford University and president of Stanford's Center for Conservation Biology.. By training he is an entomologist specializing in Lepidoptera (butterflies), but he is better known as an ecologist and for his warnings about unchecked population growth and limited resources. Ehrlich became a household name after publication of his controversial 1968 book The Population Bomb.