The Neutron and the Bomb A Biography of Sir James Chadwick. Andrew Brown. Oxford University Press, New York, 1997. 402 pp. $35. ISBN 0-19-853992-4. Brown, an English radiation oncologist, provides the first biography of the physicist who discovered the neutron, helped write the "Maud" report that led the British and Americans to pursue nuclear weapons, and was the chief British scientist on the Manhattan Project.