Career
Hordern had an extensive mechanical puzzle collection and was an author on the topic of mechanical puzzles. His best known book is "Sliding Piece Puzzles", originally published in 1986 by Oxford University Press (). In 1993, Hordern edited, corrected and privately published a Centenary Edition of the famous "Puzzles Old & New" by Professor Hoffmann, including photographs of many original puzzles of the 1890s, mostly from his own collection.