The article reconstructs Hryhoriy Mayfet’s theory of the novella, which he presented in his two-volume work The Nature of the Novella (1928–1929). The Ukrainian scholar’s theoretical suggestions fit into the general context of German and American literary critics’ search for the key features of the novella genre. The article also reveals the history of the controversy over Mayfet’s book in the Ukrainian literary process of the late 1920s and early 1930s, which took place between Volodymyr Derzhavyn, Felix Yakubovsky, and the critics of New Generation. This discussion, which lasted almost four years, demonstrates how ideological control was increasing in Ukrainian literary criticism in the early 1930s.