* The name is misspelled. Perhaps you are thinking of a different author with a similar name.
* The author is less known. There may be an author named Walter Herbert Holt with a small body of work or who writes in a specific niche.
* The author is relatively new. It's possible the author is just starting out and has not yet gained widespread recognition.
To help you find the author you're looking for, please provide more information:
* What kind of books do you think the author writes? (e.g., fiction, non-fiction, science fiction, historical fiction, etc.)
* Do you remember any specific titles or books by the author?
* Where did you encounter the name Walter Herbert Holt? (e.g., a book cover, an article, a library catalogue)
With more information, I can better help you find the author you are looking for.