Despite the many successes the "rocketry fad" could not be sustained during the early years of the Great Depression. The German public lost interest amidst economic turmoil. Meanwhile, rocket researchers, such as Rudolf Nebel, formed closer ties with the military, which greatly expanded under the leadership of Wernher von Braun. With the collapse of the VfR, the rise of a culture of necessary secrecy and the loss of public enthusiasm, Ley grew discouraged. He continued to write articles for the domestic and foreign press while he stayed in touch with close friends. Yet for the most part, Ley turned back to his original scientific interests, while writing a biography of Conrad Gessner (the "Father" of modern Zoology). To make ends meet Ley also worked as a clerk and then manager at a Berlin bank.