John Haefele's paperback (and affordable) version of
A Look Behind the Derleth Mythos is out, and I've done a review of it on
Amazon. It's a very solid book in nearly every regard, and I think adds considerably to the scholarly analysis of Derleth with regards to Lovecraft and weird fiction.
One thing that did catch my eye, which was too small to really note in the review, are the relatively frequent references to Clark Ashton Smith in the text. I don't mean that Haefele really relied on Smith to justify Derleth's fiction or business practices to much extant - but like Derleth, Smith was a writer in the Mythos who had been contemporary (and eventually outlived) both men, and so forms sort of a common point of reference in how they developed their individual parts of the Mythos. I would, one day, like to read more on Derleth and Smith's business and personal relationship - I've read their letters that have been published, but I imagine there are more, and it would be interesting to see more of what they talked about back in the day, and the circumstances surrounding the creation and sale of Smith's books at Arkham House.