Joshua Lederberg. 23 May 1925 — 2 February 2008

Abstract

When Joshua Lederberg (known to friends and colleagues as Josh) died on 2 February 2008, the world lost one of the most extraordinary scientists of the twentieth century. It is difficult to write an adequate memorial for him, or to convey on paper the outpouring of admiration and affection expressed in written and oral presentations by experts in widely diverse fields of inquiry. Even listing his various interests and achievements is a formidable task, and adequately evaluating the importance of his contributions to science and society is almost impossible. As the founding father of bacterial genetics, Lederberg was the first to demonstrate the conjugal transfer of genetic markers in bacteria. Together with his associates, he went on to make many more discoveries that laid the foundations of molecular genetics. For this work he received the 1958 Nobel Prize in Physiology or Medicine, sharing the award with G. W. Beadle and E. L. Tatum. While retaining an interest in bacterial genetics, he went on to explore and make seminal contributions to numerous other disciplines including exobiology (a term he coined), the application of computers and artificial intelligence to chemistry and medicine, and the epistemology of science. He advised US presidents and international organizations on a wide variety of issues, and devoted a prodigious amount of time and effort to the task of informing policy makers and the larger public on important scientific matters. Joshua Lederberg was a man not only of towering intellect but also of impeccable integrity and dedication to human welfare.