Admiral Zhao - For example, the manual leads one to believe that blocking an arrow with a shield merely means you get to add the shield's protection against the arrow (based on how other combat works, where the only explanation is given), which is wrong. A parried arrow is actually totally negated, which is a critical difference when planning battle tactics, and yet is never mentioned in the manual. (see pgs 74-77 - the melee combat section is a necessary read because that's where the only description of actual shield effect is).
Or perhaps the total absence of mention that fear reduces enemy morale each round of combat, which is really significant and the more important of its effects.
Other examples could of course be mentioned. In fact, there are entire threads on this board pointing out inaccuracies of the manual. Ie,
http://forum.shrapnelgames.com/showthread.php?t=39469.
James243: Maybe i'm showing my age, but I remember the manuals from the 80s and early 90s games, which were at least as good as the Dom3 manual if not better. In the 80s, RPG manuals had full spell listings with descriptions and game data, for example. So i don't consider inclusion of such things special - its a flaw with the product if it *doesn't* have such a manual.
(in the case of RTSes, the games are generally simple enough that the 'functional' manual is really all that could be expected. My copy of starcraft came with a perfectly good manual for the complexity of the game, including, most relevantly, a fold-out tech/building tree).