While the Rules Compendium is a boon for any Dungeon Master, there are a few blind spots you should be aware of. Information on rituals is slim, to put it mildly. Rituals just get a general sidebar on page 134. If you’re waist deep in the paragon tier or higher, your players are probably finding more uses for rituals. The new magic item rarity rules seem to be partially designed to free up liquid treasure for other uses, so for some of you, this will be a tad annoying. Rules Compendium also leaves out some of the rules for weapon properties in the game (, defensive, stout, and fan-favorite brutal) along with rules on double weapons. There is no mention of backgrounds (at least backgrounds with mechanical elements), themes, the piloting vehicle rules, and some other things that tend to be more DM-centric, so they will poke their heads up in the Dungeon Master’s Kit. If you use those rules in your game, you will want to supplement your Rules Compendium with a cheat sheet.