Mr Goby is a recurrent character in several Christie stories in the Poirot universe. He operates a private investigation service. Hercule Poirot uses his services especially for checking up on the backgrounds of people. He has a fairly large role in Third Girl.
- The Mystery of the Blue Train (1928)
- After the Funeral (1953)
- Third Girl (1966) - Goby supplies background information on the various key personalities, especially the Restarick family.
- Hallowe'en Party (mentioned) (1969) - Goby also has a "foreign service". Here he supplies background information on Olga Seminoff gleaned from her home country Herzogovinia. She had not returned there but had corresponded with a friend in her home town.
- Elephants Can Remember (1972)