It may come as a surprise that a comprehensive volume on the buildings by the Liechtenstein architect has never been published. A partial reason for this may be found in the ambiguous personal background of Franz Roeckle (1879–1953) and the incompatibility of his political and aesthetic stances: shortly after studying under Theodor Tischer, he won the competition for the construction of the Westend synagogue. It would become one of his most notable buildings and earned him further large-scale construction projects in the region of Frankfurt, including the hospital of the Israelite community and the Israelite nurses’ residence. The caesura came in 1923: the architect sympathized with the National Socialist German Workers’ Party, which he joined in 1932. Yet in 1924 he was in charge of the building of the Institute of Social Research. He was furthermore the architect responsible for the Riedhof residential estate under the direction of Ernst May and was instrumental in the construction of the Dammerstock colony by Walter Gropius.This publication draws on the last surviving documents and sources that allow getting an idea of this largely neglected protagonist of the New Architecture movement.