You got that at a thrift store?! And for $20?!?! That bro, is the original red box. That is worth its weight in gold. You're looking at one of the earliest rules-lite versions of AD&D and it dates back to 1983! Treasure it bro.
Quote from Wikipedia on it
1983 revision
In 1983, the Basic Set was revised again, this time by Frank Mentzer, and redubbed Dungeons & Dragons Set 1: Basic Rules. The set included a sixty-four page Players Manual, a forty-eight page Dungeon Masters Rulebook, six dice, and in sets in which the dice were not painted, a crayon. The 1983 revision was packaged in a distinctive red box, and featured cover art by Larry Elmore. Between 1983 and 1985, the system was revised and expanded by Mentzer as a series of five boxed sets, including the Basic Rules (red cover), Expert Rules (blue), Companion Rules (teal, supporting levels fifteen through twenty-five), Master Rules (black, supporting levels twenty-six through thirty-six), and Immortal Rules (gold, supporting Immortals, characters who had transcended levels). Instead of an adventure module, the Basic Set rulebooks included a solo adventure and an introductory scenario to be run by the Dungeon Master.
The 10th Anniversary Dungeons & Dragons Collector's Set boxed set, published by TSR in 1984, included the rulebooks from the Basic, Expert, and Companion sets; modules AC2, AC3, B1, B2, and M1 Blizzard Pass; Player Character Record Sheets; and dice. This set was limited to a thousand copies, and was sold by mail and at GenCon 17.
An Australian version of the Basic Set was printed by Jedko Games in 1987.
