His first book, Nixon's Shadow: The History of an Image (W.W. Norton, 2003), won the American Journalism History Award, the Washington Monthly Annual Political Book Award, and the Columbia University Bancroft Dissertation Award. Greenberg has previously served as an assistant to Bob Woodward, and as managing editor and acting editor of The New Republic. He has written for many scholarly and popular publications including The New Yorker, The New York Times Book Review, The Atlantic Monthly, Foreign Affairs and The Journal of American History. He is also the author of the "History Lesson" column at Slate.