[j. d. worthington]

I don't think it's whim on his part. From my understanding, he's had to divide it up into several volumes in order to work with the publisher's concerns. Understandably, he would not want to put all HPL's very best together in one or two volumes, leaving the lesser tales for the remaining one; and he also attempted to give an idea of HPL's growth as a writer in each volume, from early to later tales....

And the answer is: the Penguin edition is the better of the two; much more attention was paid to getting the correct text (removing the various editorial incrustations and replacing the missing passages, etc.), while the annotations are frequently both helpful and insightful....