"When the first functional prototypes of the Leica M3 became available in the early fifties, their shape had already been established to a large extent by the designers. As a sculptor, Dr. Ludwig Leitz believed that its final appearance should be determined by a stylist who can think "three-di-mensionally," like a sculptor. He also discussed this aspect with "Willi" Wilhelm Stein, head of the Photo Design Department, and with Adolf Groß, head of the Styling Department at Leitz. The latter suggested asking his former professor of sculpting for help in finding a qualified young man for this task. When Dr. Leitz subsequently visited Professor Scheuernstuhl at a college in Hannover, he met Heinrich Janke in a studio, where Janke was preparing a bust to be cast in bronze. That subject was of particular interest to Dr. Leitz, so he spent a good deal of time in an animated discussion with master student Janke about the latter's work. Janke still remembers Dr. Leitz asking him whether he knew about the Leitz company and whether he would be interested in moving to Wetzlar in order to work in a creative capacity at his company. Even though Janke showed interest in such a job, they parted company without a firm commitment. Janke had already forgotten the encounter when he was called to the telephone a few months later. The Leitz Personnel Department wanted to know when he was finally coming to Wetzlar, where he was already expected."
Text source - Osterloh, 50 Years Leica M, Königswinter 2004, p. 93-4
"Von der Konstruktionsseite für die Leica M3 sind zu nennen: Dr. Ludwig Leitz, LTG.gesammt, "Willi" Wilhelm Stein, Ltg. Konstruktion und Adolf Groß, Ltg. Formgestaltung sowie Prof. Scheuernstuhl als Bildhauer und sein Meisterschüler Heinrich Janke aus Hannover, der spätere Leiter dieser Abteilung. Später bestand das Team aus Hans-Kurt Uellenberg, H. Janke, Ernst Rühl und Bernd Nickel (von links, siehe Abb.!). Hier 3 Entwürfe für die Leica M3 aus den 50èr und 60èr Jahren. 1953, 1956, 1957 und 1961. Heute nennt man das Design oder CAD bei Leica. Eine leider früher und auch heute viel zu gering geachtete Species für neue Produkte und ihren Erfolg. Damals hats aber geklappt Grüße Hendrik" hös
Source -  #1