Known as the youngest physics professor at the University of California at Berkeley, Ernest Orlando Lawrence played a major role in the development of nuclear physics. From 1936 until his death he was director of the Radiation Laboratory at Berkeley, where he invented the cyclotron , a device that accelerates the speed of nuclear particles. The invention of the cyclotron inaugurated a new era in the study of nuclear physics, and for this achievement he was awarded the 1939 Nobel Prize in physics. At Lawrence's laboratory several radioactive isotopes were discovered; one of these was plutonium, an element essential to the development of the atomic bomb. Lawrence played an active role in the research on nuclear weapons both during and after World War II, and he remained a strong advocate of increasing America's nuclear arsenal.

Lawrence was born in Canton, South Dakota, on August 8, 1901, the eldest son of Carl Gustav Lawrence...