Ask Republican vice presidential nominee Paul Ryan how he became a conservative and he’ll probably answer by citing a book. It might be Ayn Rand’s Atlas Shrugged. Or perhaps he’ll come up with Friedrich Hayek’s Road to Serfdom, or even Barry Goldwater’s Conscience of a Conservative. All of these books are staples of the modern conservative canon, works with the reputed power to radicalize even the most tepid Republican. Over the last half-century, they have been vital to the conservative movement’s success—and to liberalism’s demise.