Although he is probably best known as the vegetarian author of Animals' Rights Considered in Relation to Social Progress (1892), Henry Salt was a man with many roles—teacher, biographer, literary critic, and energetic advocate of causes he grouped under the title of humanitarianism. These included pacifism and socialism as well as vegetarianism, anti-vivisectionism, and other attempts to promote the welfare of animals. Late in his life, Salt also advocated efforts to conserve the beauties of nature, especially wildflowers and mountain districts.

Salt was born in India in 1851, the son of a colonel in the Royal Bengal Artillery. When his parents separated a year later, Salt's mother moved to England, and he spent much of his childhood at the home of her well-to-do parents. Educated at Eton and Cambridge, he embarked on an apparently comfortable...