The Rogues Gallery was a first edition AD&D supplement devoted to providing statistics for non-player characters: adventuring parties, bandits, merchant caravans, and other commonly encountered groups of people. Erol Otus created the front and back cover art as well as five black and white interior illustrations.
(Scanning issues have created the weird pattern on the lower portion of the roper.)
A druid casts creeping doom on a mind flayer.
An owlbear encounter.
(Another scanning issue.)
The last chapter in The Rogues Gallery was titled “Personalities”. This chapter provided statistics and descriptions of legendary personages. Basically they were PCs and NPCs created by TSR staff. Erol Otus provided both an illustration and statistics for a character of his called Valerius.
This back cover art looks out-of-place on a book of NPC statistics, but in fact it is entirely appropriate. Because each such creature is unique, chapters in the Rogues Gallery were devoted to write-ups for ki-rin, couatls, and liches.
Special thanks to my good buddy Pat for loaning me his near-mint copy of The Rogues Gallery.