FUNDAMENTALS OF GAME DESIGN, SECOND EDITION
War Games
CRPGs and war games both include combat and a set of rules for determining how it takes place. However, CRPGs differ from war games in that CRPGs are about a small group of heterogeneous characters (and sometimes only one), almost always implemented as living humanoids, rather than a large group of often identical units such as tanks or airplanes. Unlike CRPGs, war games seldom keep track of the growth of individual units, and role-playing games don't normally have factories that can produce more units.
The Heroes of Might and Magic series crosses the CRPG and war game genres. The games include both individual heroes and troops who have to be managed in large battles.
Action games frequently test the player's physical skills; CRPGs never used to, but physical challenges are becoming more common in CRPGs. The Elder Scrolls games, Morrowind and Oblivion, are both action-CRPG hybrids. They feature a single avatar and a user interface much simplified from the traditional party-based model.
CRPGs include a lot of non-action-related activities such as buying and selling, as well as conversations with other characters in which the player has a choice of dialog. These activities are rare in action games.