Hear Pulitzer prize-winning historian Garry Wills and epidemiologist Devra Davis on this edition of Fresh Air.

Garry Wills' new book is about the separation of church and state written into the Constitution by our founding fathers, and the challenges to it through the rise of evangelical fervor over the years. His new book is Head and Heart: American Christianities. Wills says that, contrary to the popular notion, the separation of church and state is "the great protector of religion, not its enemy." He is the author of the books Lincoln at Gettysburg and What Jesus Meant. He is a Professor of History Emeritus at Northwestern University.

Then, Devra Davis, the author of the book, The Secret History of the War on Cancer. In the book, she argues that we are ignoring dozens of cancer-causing chemicals like asbestos, benzene, vinyl chloride, and dioxin. Davis writes that, like the tobacco companies, the chemical industry has managed to obfuscate the carcinogenic dangers of chemical and other toxic waste. Davis is the director of the Center for Environmental Oncology at the University of Pittsburg Cancer Institute, and a professor in the Department of Epidemiology of the Graduate School of Public Health. [Broadcast Date: October 4, 2007]