A seminal figure in 20th-century mathematical logic and philosophy, Bertrand Russell produced more than seventy books and pamphlets on topics ranging from mathematics and logic to philosophy, religion, and politics. He valued reason, clarity, fearlessness, and independence of judgment, and held the conviction that it was the duty of the educated and privileged classes to lead. Having protested against Britain's participation in World War I and against the development of nuclear weapons, Russell was imprisoned twice for his convictions. In writing his own obituary, he described himself as a man of unusual principles, who was always prepared to live up to them.

Bertrand Arthur William Russell was born on May 18, 1872, in Ravenscroft, Trelleck, Monmouthshire, England. His family tree can be traced back to John Russell, a favorite courtier of Henry VIII. His grandfather, Lord John Russell, served as Prime Minister under Queen Victoria. Bertrand Russell's father, Lord Amberley...