What has the author Robert E MacMaster written?

There is no widely known author named "Robert E MacMaster". It's possible there is a lesser-known author with that name, but it's more likely you are thinking of a different author, perhaps with a similar name.

Could you double-check the spelling or provide more context about the author you're looking for? For example:

* Is there a specific book or genre you're interested in?

* Are you sure about the spelling of the name?

With more information, I can help you find the correct author and their works.