Short answers, pulled from the story.
The 1977 Basic Set was written by J. Eric Holmes, an outside writer hired by TSR, Inc. Holmes based his work on Gary Gygax and Dave Arneson's original 1974 D&D rules plus the Supplement I: Greyhawk expansion. The set was designed for new players aged twelve and older.
Dave Arneson sued TSR in 1977 over royalties, arguing he should receive a percentage of the full Basic Set box price, not just the rulebook inside. TSR responded by replacing the Dungeon Geomorphs and Monster and Treasure Assortment booklets with Mike Carr's adventure module In Search of the Unknown, shifting the contested royalty money to Carr rather than Gygax.
Before September 1979, the Basic Set sold roughly 5,000 copies a month. After James Dallas Egbert III disappeared and news coverage linked D&D to the incident, sales rose to more than 30,000 copies per month by the end of 1979.
The Moldvay revision deliberately separated Basic D&D from Advanced Dungeons & Dragons rather than aligning the two. It featured a sixty-four page rulebook with a bright red cover by Erol Otus, polyhedral dice in a heat-sealed bag with a wax crayon, and continued to include the adventure module The Keep on the Borderlands, which went on to sell 750,000 copies a year.
The 1991 version, nicknamed the "black box" and officially titled The New Easy-to-Master Dungeons & Dragons Game, was designed primarily by Troy Denning. It raised the character level cap to five and introduced the Dungeon Card Learning Pack, a set of 48 cards inspired by the SRA reading program, each teaching one rule element with an accompanying scenario.
Five distinct editions of the Basic Set were published between 1977 and 1994. The original Holmes edition appeared in 1977, followed by Tom Moldvay's revision in 1981, Frank Mentzer's five-set series beginning in 1983, Troy Denning's black box in 1991, and Doug Stewart's Classic Dungeons & Dragons Game in 1994.