DR. PAUL OSTERN was killed by the Nazis in Lwow at the beginning of July 1941, during a pogrom in which several men of science, scholars, physicians and others died. Ostern is well known to biochemists all over the world: although young, he made brilliant contributions to biochemistry. Born in Zloczow in 1902, he studied medicine in Lwow, and joined my staff in 1927. Ostern was especially gifted for chemical work. Though he received no special chemical training, except in my biochemical laboratory, he was able to cope with the most difficult chemical investigations. It was he who succeeded in obtaining on a large scale not only inosinic acid from muscle but also adenylic acid: during the nineteen-thirties every laboratory which was using adenylic acid for research purposes acquired it, directly or indirectly, from the Laokoon factory in Lwow, where Ostern was collaborating, and where the preparation of adenylic acid from fresh meat was under his supervision. Only in 1937 this changed, when Ostern made his brilliant discovery of enzymatic synthesis of adenylic acid from adenosin and phosphate, the method now generally employed for the production of adenylic acid—also for therapeutic purposes.