From the publishers blurb:
This work is based on the dungeon map on page 95 of the Advanced Dungeons & Dragons Dungeon Masters Guide (DMG) by Gary Gygax. The map has 39 numbered areas and is provided under the heading of A SAMPLE DUNGEON, with the first three rooms described. A few additional clues can be gleaned from details in the text, such as the wandering monsters table mention of bandits in areas 4 and 5 and goblins in areas 7 and 8. This work describes all 39 areas of the dungeon.
The sample dungeon in the DMG is entitled “MONASTERY CELLARS & SECRET CRYPTS.”
No context is provided beyond the descriptions of the first three rooms, a couple of pages of discussion about the first dungeon adventure, and the example of play starting on page 97. The map itself is divided into two main sections. We’re going to assume one section was intended to be the Monastery Cellars and the other section the Secret Crypts. That is, the
Monastery Cellars contains areas numbered 1 through 23, and it is almost completely separate
from the Secret Crypts. The Secret Crypts section contains areas numbered 24 through 39. A single cleverly hidden secret door in room 3 connects the two sections.
This is a bundle of two PDFs - one is full color with parchment background on each page; the other is a printer-friendly version without the parchment backgrounds.