(From the Introduction page of the Rules Book:)

You've played the exciting computer RPG. Now get ready to play the world's greatest adventure game! We've set this version of the Dungeons & Dragons® game in the dark, dangerous world of Diablo II. It features the heroes and monsters from the Diablo II computer game and translates them so you can experience the fun and excitement of playing without your computer.

All you need are a couple of friends, a comfortable place to get together, a few pencils and some paper, and the contents of this box. After that, the Adventure Game and your imagination will do the rest.

CONTENTS:
Rules Book (DM Guide)
Quest Book (Modules)
Monster Folders (Bestiary)
- (over a dozen popular Diablo II basic monsters)
Character Folders (Player's Handbook/Character Sheets):
- Amazon, Barbarian, Necromancer, Paladin, Sorceress
Set of 6 Standard D&D Polyhedral Dice
DM Screen
Quick-Start Sheet
Double-sided Map Tiles:
- TILES: 9x Short Corridors 2x3"
- TILES: 9x Medium Corridors 2x6"
- TILES: 9x Long Corridors 2x9"
- TILES: 9x Small Rooms 3x4"
- TILES: 6x Large Rooms 4x5"
- TILES: 3x Quest Rooms 5x7"
- TILES: 3x Small Special Rooms 2x2"
Assorted Counters
- ??? (dozens, representing Monsters, Heroes, etc.)

NOTE: No D&D edition number is mentioned in the rules, but this game appears to use a modified pre-3rd Edition rule set (likely 2E?)