A reader was kind enough to send me this bit of background on Fingers of Fear:
"As you mention in your review, the book's enduring semi-popularity is a bit of a phenomenon--actually the result of a few overlapping phenomena. In 1937, no one published gothic horror in hardback. It was always consigned to pulps. But Nicolson had some clout because his "Canterbury Tales" had sold well not only to academic institutions but to casual readers. As a result, Covici agreed to publish "Fingers." It was not a big seller, but was noticed instantly as an oddity--a hardbound gothic horror novel in the late '30s. The story was pretty good, and the writing literate, so it developed an immediate cult following. As gothic romance grew in popularity, so did the reputation of "Fingers." This is where phenomena begin to overlap. Horror and science fiction movies enjoyed a rebirth of popularity with the purchase of the rights to the old Universal catalogue by Shock Theater. The popularity increased when Forrest Ackerman launched "Famous Monsters of Filmland" magazine. Television looked for new ways to get in on the trend, and soon "Dark Shadows" was hatched. Its creators were familiar with "Fingers of Fear." Then, when "Dark Shadows" became a hit, publishing houses looked for a way to cash in on the new popularity of gothic romance mixed with horror. Needless to say, one of the first things they did was reissue "Fingers of Fear" as a paperback. So the original book, published by chance almost as a favor to Nicolson, ended up helping to inspire "Dark Shadows," then was reissued directly as a result of "Dark Shadows." The cult following grew, and eventually Midnight House issued the celebratory hardbound reprint."
He was also kind enough to send me a copy of the original dust cover (see above).