The papers of Wilhelm Fliess (1858-1928) span the years 1894-1929 and include correspondence, writings, a reminiscence, and clippings, all of which are in German. A large portion of the papers concerns a plagiarism controversy surrounding the publication of Otto Weininger’s Geschlect und Charakter in 1903. Weininger’s book contained theories on bisexuality similar to those developed by Fliess. Fliess alleged that Sigmund Freud had discussed his theories with Hermann Swoboda who then related them to Weininger. Included is a draft and published text of Fliess’s pamphlet on the subject, In Eigener Sache . Accompanying the pamphlet are letters to and from Fliess and a clipping file concerning Fliess’s allegations.

Also featured in the papers are letters dated 1894-1898 from Joseph Breuer, a letter from Oscar Rie dated 1895, an undated draft of a writing by Fliess entitled “Die Entdeckung der Dauernden Doppelgeschlechtigkeit: Eine geschichtliche Darstellung,” and reminiscences by Fliess’s son, Conrad Fliess, contained in a letter to Richard Pfennig.