There are several authors with similar names, but none with the exact combination of "Agnes R. Riddell."
To help you find the author you are looking for, could you please provide more information?
For example:
* Do you know any other details about the author or their work? (e.g., their genre, the time period they wrote in, the title of a specific book)
* Are you sure about the spelling of the name?
With more information, I can help you find the author you are looking for.