I keep seeing references to "Core" D&D3.5e (as opposed to the SRD), but I'm not sure which books are included. I know the Player's Handbook (PHB), Dungeon Master's Guide (DMG) and Monster Manual (MM) are part of "Core", but what about the PHBII, DMG2, MM2&3, etc.? Are they considered "Core"?
If you look at the covers of the Player's Handbook (I), Dungeon Master's Guide (I), and Monster Manual (I), they say Core Rulebook I, II, and III, respectively. These are the Core rulebooks; everything else is supplemental.