| Wheelers (with Ian Stewart) | 2000 |
| Heaven (with Ian Stewart) | 2004 |
| Non-Fiction Series | |
| Discworld (non-fiction) (with Terry Pratchett and Ian Stewart) | |
| The Science of Discworld | 1992 |
| Non-Fiction | |
| The Collapse of Chaos: Discovering Simplicity in a Complex World (with ian Stewart) | 1994 |
| Figments of Reality: The Evolution of the Curious Mind (with Ian Stewart) | 1997 |
| Evolving the Alien: The Science of Extraterrestrial Life (with Ian Stewart) | 2002 |
| What Does A Martian Look Like? The Science of Extraterrestrial Life (with Ian Stewart) | 2002 |