Thomas Hayden is a freelance journalist and writer with a special interest in science, medicine and culture. Formerly a staff writer at Newsweek and U.S. News & World Report, his articles and reviews have appeared in more than a dozen publications, including National Geographic, Nature and the Washington Post. He is also the co-author of On Call in Hell: A Doctor’s Iraq War Story, which was a national bestseller in 2007. He lives in San Francisco with his wife and fellow writer, Erika Check Hayden.