Dungeons & Dragons Set 2: Expert Rules (1983)

From the back of the box:

This is Set 2. Do not buy this set until you have Set 1.

This box contains all you need to continue the Adventure:

• Endless hours of adventures.
• The D&D Expert Set for character levels 4-14, including more combat rules, magic spells, treasures, monsters and added rules for Wilderness adventures.
• Module X1, Isle of Dread. A combined wilderness and dungeon adventure on a remote island filled with savages and prehistoric monsters!
• All the dice you need - six different kinds included, with marker crayon.

This is the second set in a five-set release for the Dungeons & Dragons Basic game released from 1983 through 1986. The sets are:

Dungeons & Dragons Set 1: Basic Rules
Dungeons & Dragons Set 2: Expert Rules
Dungeons & Dragons Set 3: Companion Rules
Dungeons & Dragons Set 4: Master Rules
Dungeons & Dragons Set 5: Immortals Rules

Later, in 1992, the Dungeons & Dragons Rules Cyclopedia was released to give a comprehensive set of Basic D&D rules that covered the first four sets above in a cleaned-up manner (leaving the Immortals out to be followed up by Wrath of the Immortals).