Let me tell you a secret.
From the 1950s when he was forced out of his teaching job until his death in 1992, Isaac Asimov, without fail, met with his publisher (he used the same one for all his fiction and non-fiction works) on the same day every single week without fail.
The purpose of these meetings was to discuss book sales and publishing runs. During his lifetime, Asimov dominated the authoritative work in publishing “Books in Print” that was published every year showing which works were still in print runs and could be ordered directly from the publisher. No library or book store was without it. During his lifetime, almost all of his 500 books could be ordered directly from his publisher and it was only after his death that they cut back the number of his titles that were available.
Asimov, who was not fond of travelling, was still constantly on the go to promote his own works, both fiction and non-fiction.
So, say you’re a librarian looking to add some titles. Call up Asimov’s publisher and they will give you a great deal on the complete set of his works. In addition to filling up your fiction section, Asimov wrote works that could be included in 9 of the 10 major Dewey Decimal classifications.
But back in the day, similarly, Asimov had so many titles he would dominate the Sci-Fi section of most bookstores.