Isaiah Berlin (1909-97) was recognized as Britain's most distinguished historian of ideas. Many of his essays discussed thinkers of what this book calls the 'long Enlightenment' (from Vico in the eighteenth century to Marx and Mill in the nineteenth, with Machiavelli as a precursor). Yet he is particularly associated with the concept of the 'Counter-Enlightenment', comprising those thinkers (Herder, Hamann, and even Kant) who in Berlin's view reacted against the Enlightenment's naive rationalism, scientism and progressivism, its assumption that human beings were basically homogeneous and...