The Hustler (1926) by John Henry Mackay published under his alias Sagitta
In a blurb for the 1985 reprinting, Christopher Isherwood wrote that the novel "gives a picture of the Berlin sexual underworld early in this century which I know, from my own experience, to be authentic." It depicted the social world of "young men who prostitute themselves in Berlin, without much concern for their own sexual identity or that of their clients".