John Locke, one of the greatest English philosophers of the late seventeenth and early eighteenth century, argued in his masterpiece, An Essay Concerning Human Understanding, that our knowledge is founded in experience and reaches us principally through our senses; but its message has been curiously misunderstood. In this book John Dunn shows how Locke arrived at his theory of knowledge, and how his exposition of the liberal values of toleration and responsible government formed the backbone of enlightened European thought of the eighteenth century.