He has also collaborated with Ian Stewart to write deep books on epistemology, and the science of Discworld.
For his many services to the series The X-Files, he was affectionately lampooned in the series in the form of UFO-author Jose Chung.
Books The Science of Discworld, with Ian Stewart and Terry Pratchett The Science of Discworld II: The Globe, with Ian Stewart and Terry Pratchett Wheelers, with Ian Stewart (fiction) Figments of Reality, with Ian Stewart (non-fiction) The Collapse of Chaos, with Ian Stewart (non-fiction) Evolving the Alien - the science of extraterrestrial life, with Ian Stewart