The product is absolute nonsense, a flagrant money-grab; the illustration, however, is a definitive representation of the dungeon crawl. The main figures prepare to battle in three dimensions, while the bordering monsters, pitched in darkness, await the survivors in two (torches first, heroes; you can’t fight if you can’t see). Otus distills, in a single monochrome image, the suspense, danger, and otherworldliness of the fantasy RPG. See more early illustrations of role-playing here.
The Adventure Log is billed as the second “playing aid” produced by TSR for AD&D. The first was the AD&D Rogues Gallery (below), also from 1980, also illustrated by Otus.