It's possible:
* The name is misspelled. Perhaps you meant a different name, like "Letitia M. Moore" or "Letitia Morissey".
* The author is not well-known. There could be a lesser-known author with that name who hasn't gained significant recognition.
* The author writes under a pseudonym. Many authors choose to publish under a different name.
To help me identify the author you're looking for, could you please provide:
* Any other information you know about the author, such as their genre, era they write in, or any specific book titles they have written.
* The context in which you came across the name.
This will allow me to give you a more accurate answer.