This is the first volume of the definitive biography of Hans Krebs, one of the world's foremost biochemists. It begins with the early work of Krebs in Germany, where, working with Otto Warburg, he discovered the urea cycle in 1932. This early achievement, coupled with the discovery of the citric acid cycle, are viewed as the foundations upon which the modern structure of intermediary metabolism is built. During the writing of this fascinating history, the author not only had access to a complete set of Krebs' key laboratory notebooks, but to the man himself through five years of insightful interviews. Holmes captures Krebs' activities at a level of intimacy that reveals scientific creativity at work. The story weaves together the investigative pathway with the professional and personal life of the investigator. The Krebs biography is certain to fascinate biochemists and historians of science alike.