2012-07-28, 07:38 PM (ISO 8601)
Re: Older D&D systems questions.
Prior posters have given pretty good answers to all these questions, so I'm going to skip them except to say that yes, the Wikipedia article is a good place for an overview of how the different editions relate to each other.
Originally Posted by BIGMamaSloth
As someone who's played all of them, I can't resist putting in my two copper pieces. OD&D is probably not what you want to play, even if you can get a hold of the rules. As Roland St. Jude pointed out above, it was heavily influenced by wargaming. While there is still some charm and a few neat ideas in there (not to mention being The First) it has a very different feel compared to more modern versions of D&D. A kind of quaint charm mixed with occasional bizarre rules.
Originally Posted by BIGMamaSloth
AD&D (1st Edition) is a much more polished and complete system. With the base three books (Players Handbook, Dungeon Masters Guide, and Monster Manual) you can do pretty much anything as long as it involves fantasy adventurers killing things. It's detailed, with lots of tables and charts (although nothing approaching Rolemaster) yet is still pretty straightforward and easy to play. A part of this is that so much of the rules are effectively completely independent little systems bolted on and only mentioned in the DMG, so that it's very very easy to ignore the parts you don't like and focus on the ones you do. For example, there are extensive sections on different Diseases and Poisons, but Assassins aren't 'balanced' around having poisons so you (as the DM) can take them or leave them, as you like. It still has its eccentricities (rounds divided up into segments, Weapon vs. AC modifier tables, Level Restrictions for races) but if you want the feel of 'old school' D&D then this (or Hackmaster ) is what you want.
D&D (Basic, Expert, Masters, etc.) Is even simpler than AD&D, lacking almost all the crunchy complications, but still keeping the spirit of the game intact. If you want to spend 5 minutes rolling up characters before descending into a dungeon, yet still be keep playing those same characters for years as they quest to become gods (sorry, Immortals ) then this is the game you want. The later books (and the Rules Cyclopedia) do add a few things, like skills and extra classes, but on the whole D&D is a very simple, straightforward system that can be a lot of fun. It does keep a few D&D quirks though, like Halflings (demihumans are classes in D&D) having only 8 levels, although later books have additional xp totals and attack ranks to keep the demihumans growing in power along with their Fighter, Magic-User, Cleric, and Thief colleagues on their way to 36th level.
AD&D (2nd Edition) is a basically a cleaned up, streamlined, and slightly more balanced version of A&D 1st Edition. Different source materials should pretty much be compatible between the two editions with very little if any tweaking needed. I think it looses a little of the charm of the original edition, but I played it in different groups from the late eighties until the late nineties, when most players I knew slid away from 3rd edition into other games. The biggest changes between 1st and 2nd are probably in presentation. Most of Gary Gygax's uniquely baroque writing style is gone and the DMG is much shorter and more straightforward. Everything is organized much better than it was in 1st edition, but some unique bits like psionics are gone or moved to seperate sourcebooks. 2nd edition has lots and lots of sourcebooks; their quality varies wildly, from excellent (Castles & Crusades was mentioned earlier in the thread) to just awful (Shaman's Handbook anyone?).