Robert Nozick, 1938-2002, was a professor at Harvard whose best known book is Anarchy, State, and Utopia (1974) – a libertarian answer to Rawls’ A Theory of Justice (1971). Murray Rothbard, 1926-1995, wrote The Ethics of Liberty as his main political philosophy work.

John Stuart Mill, 1806-1873, was the most famous classical liberal. Herbert Spencer, 1820-1903, was a prominent classical liberal political theorist of the Victorian era. Lysander Spooner, 1808-1887, was an American individualist anarchist and abolitionist.

John Rawls, 1921-2002, was the most influential figure among American philosophers. His first, and main, work, A Theory of Justice (1971), made him famous. It aimed to resolve the seemingly competing claims of freedom and equality.