There are a lot of prolific Science-fiction and fantasy writers and Poul Anderson surely fit that description. From his wiki intro:
Poul William Anderson (November 25, 1926 – July 31, 2001) was an American science fiction author who began his career during one of the Golden Ages of the genre and continued to write and remain popular into the 21st century. Anderson also authored several works of fantasy, historical novels, and a prodigious number of short stories. He received numerous awards for his writing, including seven Hugo Awards and three Nebula Awards.
I have not read a lot of Anderson’s work but as I looked through the list of his books from Goodreads.com, I did recognize a number that I had picked up almost randomly over the years and read. This included some books and stories that he added to series that had been from other authors as well as parts of series or collaborations he had with others.
An example of the former is his book Conan the Rebel. Conan was started by Robert E. Howard and L. Sprague de Camp added both books and stories to the Conan universe. I do recall reading Anderson’s contribution to Conan’s ‘history’ as well.
Anderson wrote five different series by himself although not all of the books/stories within the series were closely related. Flandry was his largest series with Goodreads showing 21 total books for this series but some of these are re-issues, compilations, or foreign editions.
One of his books listed as part of the Operation Otherworld series is A Midsummer Tempest. This book is probably my favorite of Anderson’s work as it provides an interesting “what-if” scenario. The book is set during the English Civil War. The major character is Prince Rupert of the Rhine. The first hook is having trains/locomotives being invented during this time, leading to a totally different outcome to the war than what happened in our “real life.” Then it adds in the hook Shakespeare being a historian rather than a playwright and his characters being living creatures. As the Goodreads synipsis puts it:
“What if Shakespeare were a historian & his world a mortal one of men & elves? Somewhere, spinning thru another universe is a history almost like ours except for the result of a revolution or two & the earlier incidence of a few inventions. A prince called Hamlet has lived in Denmark. The English woods are full of Pucks, Titanias & Oberons. Cromwell is at the throat of King Charles, but locomotives rage thru the verdant countryside & observation balloons tower over battle lines.”
Other Anderson books I have read include Rogue Sword set during the waning days of the Roman Empire; Genesis which is a universe where the human mind can be melded to computers; and The Broken Sword using Thor and other characters from Norse Mythology.
Anderson worked mainly in the sci-fi field but he also wrote some fantasy in collaboration with his wife, Karen Anderson.
Besides his Hugo and Nebula awards, Anderson also won other awards and was a member of the Science Fiction and Fantasy Hall of Fame.
Picture from Gwydion M. Williams licensed under Creative Commons