 Ehrenfeld's work primarily deals with the inter-related topics of biodiversity, conservation, and sustainability.He is also the founding editor of "Conservation Biology", a peer-reviewed scientific journal that deals with conserving the biodiversity of Earth, and has written for various magazines and newspapers including the "New York Times", the "Los Angeles Times", and "Harper's Magazine".Ehrenfeld attended Harvard University for both his undergraduate and medical school studies, where he received his MD in 1963.