Larry Gonick’s Cartoon Histories – while they have a definite bias and they take sources like Howard Zinn seriously, they are a good overview.
Yorum Bauman’s Cartoon Introduction to Economics series – another good overview, although it leans way too heavily on Keynesianism and a since disproven view of the imminent collapse of capitalism.
Niall Ferguson’s The Ascent of Money: A Financial History of the World – not only a good overview of the history of economics, but a good analysis on why things did and didn’t work.
Byzantium: The Surprising Life of a Medieval Empire by Judith Herrin – an overview of the history of one of the most important empires in history as well as a good insight into how large, long-lasting empires actually work
K’ang-Hsi’s autobiography Emperor of China – what it is like to be the emperor of a stable, strong empire.
A History of Venice by John Norwich – how a small, scrappy city-state not only stood up to the empire, but how it caused the end of the empire doing it while becoming a major world power in its own right.
Marx’s Communist Manifesto – an excellent example of utopian propaganda.
Evgany Zamyatin’s We – what a Marxist/Leninist utopia looks like from the inside by a founding member of the Bolsheviks.
St. Thomas More’s Utopia – a satiric look at utopian propaganda.
Plato’s Republic – If you haven’t read this by now, you should. Gets almost everything wrong, but in important ways. The Allegory of the Cave still works, both as an illustration of the incompleteness of knowledge and how an egomaniac views themselves.
Fifth Edition Dungeon Master’s Guide – In addition to teaching you how to run the world’s best game, the DMG is full of excellent advice on creating characters, societies, and economies.