It's possible that:
* The name is misspelled. There could be variations like "Robert Russell" or "Rob Russel." If you can provide any other details like the genre of books, the author's nationality, or a title of a book, it might help to narrow down the search.
* The author is less well-known. It's possible that the author is published independently or within a niche genre.
To help you find the author you're looking for, please provide more information about the author or their works.