Ah, Deities & Demigods. This book, in two 1980 printings, was legendary to a younger version of myself. I don’t know how I learned that it contained entries for the Cthulhu Mythos and Michael Moorcock’s Elric, but I did, and I wanted it. It took years to track down a copy. It remains one of a
handful of RPG books I consider to be worth whatever obscene price they’re asking for on eBay. (This is a first printing of the first edition – credit to Chaosium appeared in the second printing, before TSR excised the material completely)

Jeff Dee’s art for the Egyptian pantheon always stood out for me (thanks, in part, to the boobs, probably) while Paul Jaquays’ Nehwon illustrations might have defined Fritz Leiber’s stories for me if Mike Mignola hadn’t come along. Dee’s take on Elric is delightfully 70s, while I can think
of no one I’d more want to illustrate the Cthulhu mythos than Erol Otus with his squishy compositions.  

As a compendium of mythology, I love Deities & Demigods. As an RPG supplement, though, it never worked for me. It always seemed strange that the gods were presented in the same way as the monsters in the Monster Manual. Surely, players aren’t supposed to fight these rarified entities. But then, why give stats if that weren’t the case? I think I always expected the book to take an approach closer to RuneQuest’s 1979 supplement, Cults of Prax, which focused on how various religious organizations worked, rather than the details of their gods. D&D wouldn’t scratch that itch in a serious way until Planescape in 1994.