General/legal theory
The Law (pdf) by Frederic Bastiat
The Ethics of Liberty [pdf] by Murray N. Rothbard
Egalitarianism as a Revolt Against Nature and Other Essays [pdf] by Murray N. Rothbard
The Structure of Liberty: Justice and the Rule of Law by Randy E. Barnett
The Enterprise of Law: Justice Without the State by Bruce L. Benson
Boundaries of Order: Private Property as a Social System by Butler Shaffer
In depth and/or specific histories
Anarchy and the Law: The Political Economy of Choice Edited by Edward P. Stringham
Law and Revolution: The Formation of the Western Legal Tradition by Harold J. Berman
Law and Revolution II: The Impact of the Protestant Reformations on the Western Legal Tradition by Harold J. Berman
Viking Age Iceland by Jesse L. Byock
The Law of the Somalis: A Stable Foundation for Economic Development in the Horn of Africa by Michael van Notten