Theodore “Dash” Hardeen (born Ferenc Dezső Weisz (Hungarian name order: Weisz Ferenc Dezső), March 4, 1876 – June 12, 1945), known simply as Hardeen, was a Hungarian magician and escape artist who was the younger brother of Harry Houdini. Hardeen, who usually billed himself as the “brother of Houdini”, was the founder of the Magician’s Guild. Hardeen was the first magician to conceive escaping from a submerged straitjacket in full view of the audience, rather than behind a curtain.

A poster for Hardeen Houdini’s magic show: ‘Hardeen inherits his brother’s secrets. Houdini’s will makes possible the continuance of Houdini’s master mysteries.’ As shown by this poster, Hardeen used testamentary language in his advertisements in an effort to position himself as Houdini’s heir in magic.

The poster was printed by Carey and Sons Lith. of New York, c. 1936. The Library of Congress says, ‘Under the terms of Houdini’s will, the Library of Congress inherited the magic and spiritualism components of the great mystifier’s library. Beatrice Houdini received the Theater Collection, now at the University of Texas at Austin. Apparatus and other stage effects were bequeathed to Hardeen.’