John Stuart Mill has held the attention of the reading public of the Western world longer than any other 19th-century philosopher, with the notable exception of Karl Marx.
Each man is known as theorist of one central idea. Marx is read by his admirers as a champion of equality. Mill is read for his words on liberty, words that have contributed much to the debates of our own time about the freedom of dissenters, minorities, and women. He was always controversial. William Gladstone, the great Liberal...