Posen worked as a consultant for the RAND Corporation and an analyst for the Department of Defense and Center for Strategic and International Studies before becoming an assistant professor of political science at Princeton University in 1984.
[1] Posen has also published a number of highly influential journal articles, including "The Security Dilemma and Ethnic Conflict" and "Command of the Commons: The Military Foundations of U.S.
Posen's first book, The Sources of Military Doctrine: France, Britain, and Germany Between the World Wars, was published by Cornell University Press in 1984.
Posen's third book is Restraint: A New Foundation for U.S. Grand Strategy, which was published as part of the Cornell Studies in Security Affairs series in 2014.
Reviewer William Ruger, writing in The American Conservative, called the book the "defining treatise" for supporters of restraint.