There is no widely known author named "Leonard P. Barnett." It's possible this name is a misspelling or a less common name. To help you find the author you're looking for, could you please provide more information?
For example:
* Do you remember any titles of books they wrote?
* What is the general subject matter of the books?
* What is the approximate time period of the books?
With more information, I can try to identify the author you're thinking of.