- The Emerald Conspiracy (Usborne Puzzle Adventures, No 18)
- Codes and Ciphers
- The Invisible Spy (Usborne Puzzle Adventures, No 17)
- Puzzle Adventures: The Pyramid Plot/the Emerald Conspiracy/the Invisible Spy (Usborne Puzzle Adventures, Book 3)
- The Crimebusters Investigate (Usborne Puzzle Adventures, 25)