(1872-1970) an English philosopher and writer. He began his career as a writer on mathematics and logic, and his best-known early book is Principia Mathematica (1910-13). He also taught philosophy, and in 1912-13 Ludwig Wittgenstein was one of his students at Cambridge University. In 1931 he became the 3rd Earl Russell. Among his other works are popular books on philosophy, education and social issues, and his History of Western Philosophy (1945) was particularly successful. He won the Nobel Prize for literature in 1950. In the later years of his life he was famous for his strong political opinions. He became the first president of the Campaign for Nuclear Disarmament in 1958.