Question: What company published a fantasy tabletop role-playing game originally designed by Gary Gygax and Dave Arneson that has a book of rules that lack the complete set of rules for the game, and only includes rules for use by players of the game?
Sentence (from "Player's Handbook"): Additional rules, for use by Dungeon Masters (DMs), who referee the game, can be found in the "Dungeon Master's Guide".
Relevant evidence: No