The Principia Discordia is a Discordian religious text written by Greg Hill (Malaclypse the Younger) and Kerry Wendell Thornley (Lord Omar Khayyam Ravenhurst). It was originally published under the title "Principia Discordia or How The West Was Lost" in a limited edition of five copies in 1965. The name, meaning "The Principles of Strife", deviates from correct Latin which would read Principia Discordiæ.
The Principia describes the Discordian Society and its Goddess Eris, as well as the basics of the POEE denomination of Discordianism. It features typewritten and handwritten text intermixed with clip art, stamps, and seals appropriated from other sources, possibly in violation of copyright laws.
While the Principia is full of literal contradictions and unusual humor, it contains several passages which propose that there is serious intent behind the work, for example a message scrawled on page 00075: "If you think the PRINCIPIA is just a ha-ha, then go read it again."
The Principia is quoted extensively in and shares many themes with the science fiction book The Illuminatus! Trilogy by Robert Shea and Robert Anton Wilson. While Wilson was not directly involved in writing the Principia, both the letter signed "Mad Malik" and the stamps used were his.
Notable symbols in the book include the Apple of Discord, the pentagon, and the "Sacred Chao", which resembles the Taijitu of Taoism, but the two principles depicted are "Hodge" and "Podge" rather than yin and yang, and they are represented by the apple and the pentagon, and not by dots. Saints identified include Emperor Norton, Yossarian, Don Quixote, and Bokonon. The Principia also introduces the mysterious word fnord, later popularized in The Illuminatus! Trilogy; the trilogy itself is mentioned in the afterword to the Loompanics edition, and in the various introductions to the fifth editions.