Arkham's Masters of Horror is a fairly good compilation of some of the lesser known works by authors who wrote for Weird Tales Magazine, and of those who were subsequently published by August Derleth, the co-founder (along with Don Wandrei) of Arkham House. Editor Peter Ruber gives some interesting, though somewhat biased, biographical sketches of each author. As other reviewers have noted, Ruber doesn't seem to like many of the authors. As editor it is Ruber's prerogative to give his opinon; I just wish that he had spent more time discussing the authors' lives and works, and less time discussing their difficult and often unethical business dealings with Derleth.
As previously noted, this book has its share of editing errors. I found several word omissions, mixed up sentences, and one glaring birth-to-death date error for writer E. Hoffmann Price who, according to the book, was born in 1998 and died in 1988. Perhaps the most glaring error is on the front cover, where the title is set incorrectly as ARKHAMS MASTERS OF HORROR (note the missing apostrophe indicating the possessive), but correct on the spine lettering as ARKHAM'S. I can't help wondering how that one slipped by.
On the plus side, Ruber includes some of the correspondence between Derleth and the various authors. You can ignore the business talk if you like, and just concentrate on the more interesting parts, such as Ray Bradbury's discussion of his works and of his relationships with other writers. Often I found these bits of correspondence more interesting than the stories themselves (though Bradbury's story "The Small Assassins" is quite good). I'd like to see some updated letters collections or bios published for some of these authors (listen up Arkham House, Hippocampus, Night Shade, &c &c).
Despite the mistakes, biases, and so forth, I found ALL of the book interesting, and I'll be looking for more works by these authors, many of whom I had heard of, but had not previously read. Mary E. Counselman, David H. Keller, Henry S. Whitehead, and Nelson Bond in particular will get my further attention.