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Harry Houdini (March 24, 1874 - October 31, 1926), born Erik Weisz, later spelled Ehrich Weiss, was one of the world's greatest illusionists and a noted debunker of spiritualists, mediums, and psychics. He is best known as an escape artist, particularly the "water torture" trick where he would escape from inside a locked tank of water while suspended upside down. Houdini took his stage name as an homage to the famous French magician, Jean Eugène Robert-Houdin.
Houdini's quest to expose fraudulent spiritualists began after the death of his mother. Heartbroken, he sought out a medium through which to contact his deceased parent. However, he discovered these mediums to be nothing more than frauds, using some of the same tricks he used on stage to scam innocent people. Houdini then embarked on a journey to debunk mysticism and the occult wherever he found it.
Houdini started a tradition which has been honored by many later stage magicians and illusionists, most notably James Randi and Derren Brown. His debunking activities, where he exposed what he called "humbug", were a direct inspiration for Penn and Teller when they devised Penn & Teller: Bullshit!. (In Houdini's day, "humbug" was the exact equivalent of "bullshit", but today doesn't carry the same force of meaning, so Penn & Teller went with the more up-to-date, if somewhat vulgar, term.)
Perhaps the closest he came to being tricked was in the instance of Mina Crandon. Sir Arthur Conan Doyle was easily fooled by her; however Houdini suspected her of fraud. His hypothesis of how she faked an ectoplasmic hand was not correct though. Houdini suspected her physician husband grafted trachea onto her genitalia to give the appearance of a dead, unworldly hand; biologists however determined the hand to be made of animal liver and found no signs of being temporarily surgically attached to Mina Crandon. 
- A Magician Among the Spirits, a book by Houdini debunking spiritualism and psychics. (Not public domain in the U.S., but it is in Europe and countries where the copyright term is life+70 years or less.)
- Miracle Mongers and Their Methods, by Harry Houdini, which exposes a number of magic tricks.