Warhammer first edition seems a surprisingly common item. It contains 3 rulebooks as seemed mandated by D&D and has options for both role-playing and wargaming. Compared to what was to come, the look is surprisingly drab.

Next to it is the very colorful 3rd edition which seems to have gotten things together pretty well, with full coverage of the wargaming rules.

Here is the 6th edition. Games Workshop discovered the benefits of planned obsolescence and rulebooks will soon go out of date so there are always more to come. There is a shift here to a handy paperback format and next to it is a very nice short rulebook which removes a lot of the fluff in the big book. These are usually included in large introductory game packs.

By now, every type of army has its own special book. That was one of the beauties of Warhammer, the complexity was in the chrome rather than the underlying core ruleset. At this stage, though, even the chrome was limited especially with what appears to be the first book of army lists, Ravening Hordes which was soon followed by a more plush book Warhammer Armies.

Army lists allow a player to determine a suitable makeup for an army providing troop types, statistics and point values. With Warhammer, this usually means some figures will be mandated, others optional with point values determining just how many options are available. Point values also are meant to insure army equity so that 2 players can feel reasonably certain that if the points values are equal, the armies will be. Additionally, increasing total points will usually increase the complexity and length of a game.

Likely an abortive attempt to sell the Warhammer fortress, there is a big book of siege rules that cover both Warhammer and Warhammer 40K. There is no compelling need to use the rules with the fortress. A 2-dimensional layout should do just as well.