Lambros Callimahos won world renown as a flute virtuoso before serving in the Army cryptologic unit in World War II. He was technical assistant to Mr. Friedman, with whom he collaborated on the classic texts, Military Cryptanalytics, Parts III. He was the author of many monographs, studies, and articles, including one on cryptology in the Encyclopaedia Britannica. For over twenty years Mr. Callimahos taught the Agency's most advanced course in cryptanalysis, Intensive Study Program in General Cryptanalysis. At the time of his death in October 1977, Mr. Callimahos had taught 32 classes and over 270 students.