In April and early this month, I started adding to my collection of philosophy and political theory (aka political science) books.
Rene Descartes
--Discourse on Method
--Meditations on First Philosophy
Carl Von Clausewitz
--On War
Thomas Hobbes
--The Leviathan
Jean-Jacques Rousseau
--Discourse on Inequality
--Discourse on Political Economy
--On Social Contract
Benedict de Spinoza
--A Theologico-Political Treatise
--A Political Treatise
John Stuart Mill
--On Liberty
--Utilitarianism
--Considerations on Representative Government
--The Subjection of Women
John Locke
--Two Treatises of Government
I already have Art of War by Sun Tzu, The Prince by Niccolò Machiavelli, The Federalist by Hamilton, Madison, & Jay, and The Communist Manifesto by Karl Marx & Friedrich Engels; however I am open to suggestions that anyone has to add to my collection.