Introductory/general
Neither Liberty Nor Safety: Fear, Ideology, and the Growth of Government by Robert Higgs
Wall Street, Banks, and American Foreign Policy (pdf) by Murray N. Rothbard
Beyond Fundamentalism: Confronting Religious Extremism in the Age of Globalization by Reza Aslan
Advanced/specialized
The Costs of War: America’s Pyrrhic Victories ed. by John Denson
Depression, War, and Cold War: Studies in Political Economy by Robert Higgs
The Myth of National Defense [pdf] ed. by Hans-Hermann Hoppe
Particular war histories
Emancipating Slaves, Enslaving Free Men: A History of the American Civil War by Jeffrey Rogers Hummel
The Swiss and the Nazis: How the Alpine Republic Survived in the Shadow of the Third Reich by Stephen Halbrook