The
Rules Cyclopedia (1991) is an excellent product, one of the very best in D&D's history. I got it shortly after picking up one of the early 1990's introductory D&D boxed sets, and it kept me captivated for a very long time.
One thing to note is that it's in fact a compilation of the first four of the BECMI boxed sets. That is, Frank Mentzer's
Basic (1983),
Expert (1983),
Companion (1984), and
Master (1985) rules. It didn't, however, try to include the "I" part of the acronym: the
Immortals (1986) set (that, instead, got its own redux release as the 1992
Wrath of the Immortals boxed set).
While those boxed sets easily predate AD&D 2E (1989), there were several iterations of the game that came out before them in turn. Strictly speaking, Tom Moldvay's
Basic Set (1981) and Marsh and Cook's
Expert Set (1981) both predate BECMI, for instance, even though most of the rules are identical. AD&D 1E was released across three years, with the
Monster Manual coming out in 1977, followed by the
Players Handbook in 1978, and finally the
Dungeon Masters Guide in 1979. 1977 was also when the original
Basic Set came out, written by Dr. J. Eric Holmes.
And of course,
Original D&D came out in 1974.