In 1904, Berlin did not exactly look like a haven of tolerance. Sex between consenting males and gender non-conformity were illegal, and other forms of sexual expression faced oppressive societal taboos. But despite fear, secrecy, and blackmail, Germany’s imperial capital nurtured a vibrant and diverse queer subculture. In Berlin’s Third Sex, German sexologist Magnus Hirschfeld offers a sympathetic glimpse into this queer life, depicting spaces such as gyms, bars, cafés, aristocratic drawing rooms, and tenement apartments that drew the 'third sex' – exiles from contemporary gender and sexual norms. Intimate, striking, and surprisingly sentimental, Hirschfeld’s account takes us from drag king cavaliers at all-night lesbian balls to 'uranian' men darning socks for their soldier sweethearts, and from cigar-smoking trans men to sex workers in moonlit parks. Hirschfeld reveals vast networks of clandestine connections: coded vernacular, camp aliases inspired by pop culture, encrypted