Bertrand Russell (1872-1970) is one of the most important philosophers of the 20th century. This account of his life and work introduces both his technical contributions to logic and philosophy, and his wide-ranging views on education, politics, war, and sexual morality. Russell is credited with being one of the prime movers of analytic philosophy, and with having played a part in the revolution in social attitudes witnessed throughout the modern world. This introduction gives a clear survey of Russell's full range of achievements.