It's possible that:
* The name is misspelled. Perhaps the author's name is similar but spelled differently.
* The author is not widely known. They may be a self-published author or someone who writes in a niche genre.
* There is a misunderstanding. It's possible you are thinking of a different author, or the name was mentioned in a context other than writing.
To help me find the author you're looking for, please provide more information, such as:
* The genre of their work: What kind of books do they write?
* Any specific titles: Do you know the name of any books they've written?
* Any other details: Where did you hear the name Larry Nielson mentioned?
With more information, I may be able to help you find the author you're searching for.