I am not sure Gary's version of history is completely in line with the external evidence, but I am not going to push any further. I have corrected spellings from the original (both mine and Gary's) but have changed nothing else. After-the-fact comments are labelled as such.
EGG: I don't believe that I ever received your email, or possibly I did and not recognizing it as a personal communication deleted it in the usual morning SPAM-deletion frenzy. Short answer about the gnoll. I created it out of whole cloth based on the fantasy creature "gnole" that I first read about in the Magazine of F&SF back in the 1950. To correspond with the 8 levels of fighters in the original D&D game I decided upon eight levels of humanoids--kobolds, goblins, orcs, hobgoblins, gnolls, bugbears, ogres, trolls. Giants were a class unto themselves. (Comment: This is a bit out of sync with the record; there were NINE levels of fighters, and Bugbears were not introduced until the "Greyhawk" supplement in 1976.)
PDH: Were you the person who added gnolls to the original edition of D&D? If not, who did so?
EGG: It was I who created the gnoll for the D&D game.
PDH: Have you read/ are you familiar with Lord Dunsany's 1912 story, "How Nuth Would Have Practiced His Art Upon the Gnoles"?
EGG: I was not at the time I wrote these humanoids into the game. (Comment: INTERESTING, particularly in light of later answers.)
PDH: Have you read/ are you familiar with Margaret St. Clair's (writing as Idris Seabright) 1951 story, "The Man Who Sold Rope to the Gnoles"?
EGG: Absolutely, and that is how I determined that "gnolls" were humanoids, albeit not small ones as the gnoles in said story. (Comment: Gary misremembers the story; there is nothing in it to imply St. Clair's gnoles were small. Also, St. Clair's gnolls were NOT "humanoid" at all; they looked like "a Jerusalem artichoke made of India rubber", and had tentacles...)
PDH: Were you the person who started the "cross between gnomes and trolls" joke? If not, who did?
EGG: Yes, it was I that suggested that for these humanoids. That was before they appeared in the D&D game.
PDH: I get the impression from the text that the original intention (in 1974) was to include Dunsany's gnoles as such, and that the "gnoll" spelling was an error of some sort, but that in 1977, with the "Monster Manual", you chose to preserve the "gnoll" spelling in light of the difficulties with the Tolkien estate over the earlier use of "ent" and "hobbit". Is this accurate?
EGG: No. I always intended to spell the name for the humanoid race as "gnoll."
PDH: The reason I had assumed that the "gnoll" spelling was a mistake in
1974 was the fact that Lord Dunsany was mentioned by name in the 1974
gnoll description. My thinking was that if you wanted to distance your
creatures from Dunsany, you would not have included his name, and that
since you DID include his name, you must have been intending you use
his creatures as such (as was done with "hobbit" and "ent"). My
confusion is further increased by the information that, as of the
publication of D&D in 1974, you had not yet read the Dunsany story. I would be fascinated to know anything you can tell me about the
process that led that entry to being worded the way it was.
EGG: There is nothing of substance to tell you. I liked the name "gnole" but
wanted to create a different sort of nasty humanoid, so I made the gnoll
large and with hyena-like characteristics--al; quite unlike their gnole. In short, as with most of the creatures I made up, I used my own imagination. (Comment: We are a bit off the rails, here. Of the various monsters in the 1974 "Monsters and Treasure" booklet from the 1974 D&D box, exactly ONE of them lists a literary source: Gnolls. Tolkien is mentioned as a source for additional details in the Orc entry, and it is stated that Tolkien's Nazguls should be classed as Spectres in the Spectre entry, but no other entry lists a SOURCE. I would think that that distinction is worthy of SOME comment, particularly since Gary admits he had not READ Dunsany as of the publication of D&D; Gary is not willing to discuss it.)
PDH: Were you the person who decided to describe gnolls as hyena men in the first Monster Manual?
EGG: No, I described them as hyena-like. Thus they are hairy, have a bad odor, and the female gnolls are larger and stronger than the males, a pack of gnolls is led by a female. (Comment: Again, this doesn't match the record. The "Monster Manual" entry makes no mention of female gnolls at all, and states that the gnolls occasionally have a king.)
PDH: While gnolls were not explicitly stated to be anthropophages until the 1989 AD&D 2nd Ed Monstrous Compendium (after you had left TSR), gamers generally assumed such behavior due to the gnolls' connections to hyenas and ghouls. Was this your intention all along?
EGG: No, I envisaged the gnoll as a humanoid that bore a resemblance to hyenas,
but belonged to the same general phylum as the other humanoids. In my
creation, kobolds were not scaly and of reptilian origination. (Comment: It seems that Gary parsed "anthropophage" as "anthropomorph", and answered the question from that perspective. Still, the information that "humanoid" was intended to be a biological classification, and not just a functional one, is interesting.)