The D&D Rules Cyclopedia is supposed to cover the same ruleset as the Basic, Expert, Companion and Masters D&D Boxed Sets.
Are the rules the same? Does it use the same text, or is it a rewrite that is supposed to cover the same rules?
I especially want to know what is in the boxed sets that is not in the Cyclopedia.
There are numerous minor wording changes, and a few more important changes.
The biggest is that the Basic Set's "1d6 damage for everything" option is gone.
There are minor changes to a few modifiers.
The attack ranks and fighter option for high-experience demihumans are on the class's XP table, making it easier to implement them.
General Skills are included from Hollow World and the GAZ series; demi-humans taking thief skills as general skills is not.
Some of the GAZ maps are included, along with large scale overviews of the Known World and the Hollow World, along with a few pages of descriptions - a few paragraphs per country.
There is a chapter of optional rules, including allowing demihumans and mystics through level 36.
The encounter rules include some expansions.
IIRC, there are a few extra monsters.
There is a conversion guide to/from AD&D 2E for using AD&D modules.
Note that none of the HW nor GAZ special racial classes are included; only the core three demihuman racial classes (Elf, Dwarf, Halfling) are present, tho' 36 levels are available in the appendix.
Note also that there is a comparable basic set: Denning's big black boxed Basic D&D. It's levels 1-5, and no general skills nor weapon mastery, but otherwise the same as Alston's Cyclopedia.
The Mentzer Immortals box was not included; it was reworked into Wrath of the Immortals, and had some major rules differences; the two are not really compatible with each other.
BECM were developed from OD&D (1974) and Moldvay/Cook Basic/Expert (1981-82), omitting various AD&D (1e) traits and expanding the original D&D game as a separate rules set. The series added many new campaign details (Dominions, the War Machine mass combat model, etc.) previously only minimally addressed by Perren (in the original 1970 Chainmail) and Gygax & Arneson (in Original D&D).
This changed notably with the RC when, in a major break from the traditional setup, Allston broke away from the traditional class archetypes and added Skills, making the game more similar to AD&D 2e. (The D&D line was phased out during this period, and the BECMI campaign setting of the "Known World" was also renamed "Mystara" and ported into AD&D2e. The Advanced game was then renamed D&D [v3] in 2000.)
As a more minor point, the Jousting rules were omitted in the RC, apparently for space reasons, and most of the artwork was changed.
Okay, going by the amazon reviews here, the wikipedia entry here, and the retroroleplaying's page on it here, it appears that the rules are overall the same, but that at least some editing was done to compile the sources. This would mean that the box set would have superseded rules.
