Crosby's landmark 1972 work argues that environmental factors shape our history just as much as-and sometimes more than-human factors.

Sen's 1997 work argues that the success or failure of international development cannot be measured by income alone.

Amartya Sen's Inequality Re-Examined is a seminal text setting out a theory to evaluate social arrangements and inequality. By asking the question, 'equality of what'?, Sen shows that (in)equality should be assessed as human freedom; for people to have the ability to pursue and achieve goals they value or have reason to value.

For decades, social scientists had used a mythical figure to describe how humans make decisions: homo economicus. He was logical and conscientious. To make a decision, he would evaluate all the options open to him, then choose the most rational course of action.

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

How many books can claim to be so influential as to inspire the development of a whole school of thought? Metaphysics did exactly that, laying the foundations for a new branch of philosophy concerned with the cause and nature of being.

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.

Politics was one of the first books to investigate the concept of political philosophy and the starting point of political science studies as we know them. Written in the fourth century B.C.E., it explores how best to create political communities that support, serve, and improve citizens.