* Typo: The name might be misremembered or misspelled. Could you double-check the spelling?
* Pseudonym: "Hap Hatton" could be a pseudonym used by a known author. Do you know anything else about this author, like genres they write or any other books they may have written?
* Unpublished: Perhaps "Hap Hatton" is an unpublished author. In this case, there's no record of their works.
Please provide more information about "Hap Hatton" or any other details you remember, and I'll do my best to help you find their works.