Claim: Fantasy Masterworks is a series of British paperbacks that were called the most influential fantasy ever written, with a seperate line featuring science fiction novels.
Evidence: Fantasy Masterworks is a series of British paperbacks intended to comprise "some of the greatest, most original, and most influential fantasy ever written", and claimed by its publisher Millennium (an imprint of Victor Gollancz) to be "the books which, along with Tolkien, Peake and others, shaped modern fantasy." A separate Future Classics line has also started featuring eight science fiction novels from the last few decades.