An interesting bit of trivia about August Derleth, one of the founders of Arkham House, was that he was a comic collector. In this 1966 letter (image saved from eBay listing) he claimed that he owned the largest collection of comics in the world.
Wikipedia says: "Derleth's papers and comic book collection (valued at a considerable sum upon his death) were donated to the Wisconsin Historical Society in Madison."
If I recall correctly, there were a ton of high grade pulps sold on eBay in 1999 or 2000 that were attributed to being part of the Derleth collection. Can anyone remember this? Or, was it another noted pulp creator's collection?