![](https://islandpress.org/files/files/2008/09/sevenstepsbanner_1.jpg)
Paul R. Ehrlich is a co-founder with Peter H. Raven of the field of co-evolution, and has pursued long-term studies of the structure, dynamics, and genetics of natural butterfly populations. He has also been a pioneer in alerting the public to the problems of overpopulation, and in raising issues of population, resources, and the environment as matters of public policy. Ehrlich is the author of The Population Bomb, and many other books, as well as hundreds of papers.