This is the biography of one of the most original and widely significant, yet largely forgotten, British scientists. Frederick Soddy is an intriguing figure who was deeply concerned with and involved in politics, economics, and the role of science in the world. He was one of the firstgeneration of English atomic scientists, working with Rutherford on the initial discoveries about atomic disintegration, and received the Nobel Prize in 1921 for hi research on isotopes. Soddy's worry about the responsibility of science and scientists to society began with his fear that the atomicenergy he and Rutherford had discovered could be disastrous if suitable political controls were not enforced, and led to his abandoning scientific research. He lived to see his worst fears realized with the bombing of Hiroshima and Nagasaki. Soddy was a pioneer in the field of energy conservationand environmental ethics, and was committed to social reform. Frederick Soddy was a remarkable and talented man who was not recognized as such in his own life-time, largely because his ideas and attitudes did not fit in with the times in which he lived. However he has become more appreciated sincehis death, not only because his scientific work has gained its rightful recognition, but also because of the increased awareness today of the environment and the role of science in it.