200 years after it was written, Adam Smith published The Wealth of Nations is still debated by governments internationally. Smith argued that 'mercantilism'-the theory that the national economy exists solely to strengthen the government, thus the government should regulate the economy-was wrong.

One of the most vital and controversial works in twentieth-century world moral philosophy, After Virtue (1981) examines how we think about, talk about, and act out our moral views in the modern world.

Albert Hourani's A History of the Arab Peoples is unsurpassed as an overview of Arab history from the rise of Islam to the late twentieth century. Going far beyond political history, it provides a deep analysis of social, cultural and economic structures.

Democracy in America, published in 1835 and 1840, challenged conventional thinking about democracy when it first appeared and is still cited today for its in-depth analysis of what makes a successful democracy.

Sen's 1997 work argues that the success or failure of international development cannot be measured by income alone. Having grown up in India, Sen brings his own understanding of poverty to the issue, arguing that the end goal of development must be human freedom.

Published anonymously by Locke in 1689, Two Treatises claims that a monarch's right to rule does not come from God, but from the people he rules. In the mid-seventeenth century, England removed its king and tried different systems of government before opting to restore a monarchy.

An important Marxist work, Prison Notebooks (1948) argues that we must understand societies both in terms of their economic relationships and their cultural beliefs.

Aristotle, a student of Plato, wrote Nicomachean Ethics in 350 BCE, in a time of extraordinary intellectual development. Over two millennia later, his thorough exploration of virtue, reason, and the ultimate human good still forms the basis of the values at the heart of Western civilization.