This biography considers the impact of a remarkable individual on a number of issues in Britain during the late 19th and early 20th centuries and makes a contribution to the political and cultural history of the period. The son of a Unitarian minister, Perris devoted his life to many causes including the Peace Movement, the promotion of international understanding, the encouragement of democracy at home and abroad, particularly in Tsarist Russia, and the development of new policies to replace laissez-faire capitalism. He was a successful journalist, prolific author and pamphleteer. In the field of publishing, Perris founded one of the early literary agencies and originated the Home University Library, which provided specially commissioned cheap, authoritative introductions to academic subjects for general readers. In 1914, breaking with many of his radical friends, Perris became a principled supporter of the war he believed to have been caused by unprovoked German aggression. He was a distinguished correspondent with the French armies for the London Daily Chronicle and was an early supporter of the proposed League of Nations.