Project Xanadu® is the original hypertext project — the brainchild of Ted Nelson, and the result of careful and passionate work by innumerable clever people over the course of nearly sixty years. Because of the length of its development period, the project has spawned and used many ideas of varying importance, and particularly important ideas have had many names. Because its history spans several eras of computing, ideas spawned by the project that were once considered radical have become commonplace and other ideas that were once commonplace have become forgotten and become radical again. Over this time, most documentation available to the public has been written by Ted, and intended for a non-technical or semi-technical audience.