For me using Amazon.ca, a search on Anne McCaffrey, english, kindle came up with 107 results. Scanning through those results, 36 of them were not by Anne McCaffrey or Todd McCaffrey. Books such as Patricia C. Wrede's
Dealing With Dragons Margaret Weis's Mistress of Dragons,
The Constitution of Canada by The Founding Fathers.
Switching to clicking on Anne McCaffrey in the author list for a book, english, kindle dropped the number of books to 81 though this included books such as
Principles of Political Economy by Wilhelm Roscher and
Peter Pan by James M. Barrie and several anthologies in which an Anne McCaffrey story is found.
I did find it rather humorous that both Kobo and Amazon (.ca and .com) included Peter Pan in a list of Anne McCaffrey books.
Oddly a quick Google search for an Anne McCaffrey bibliography came up with several listings that I found better including
WikiPedia's entry.
To me, this pretty much proves that if you want decent search results, use a search engine that is not tied to the store you are searching.