Psionicist said:
Great! I was very bothered that Sword & Sorcery Studios called Relics & Rituals "Core book 4" (or something like that).
S&S labelled CC1, R&R, and CC2 as "Core Rulebook".
KenzerCo put "Rulebook IV" on the cover of the Kalamar Player's Handbook (but they are not restricted by the d20 STL).
You confused both.
Anyway, product names like
Seafarer's Handbook are still valid. What isn't is Player's Handbook, Dungeon Master's Guide and Monster Manual (so, you could not release an "Ultimate Monster Manual" or "Monster Manual 2004" or whatever).
You can still use Player, Handbook, Dungeon, Master, Guide, Monster, and Manual, just not in a two- or three-word combination that would liken it to something made by WotC. (Incidentally, a Dungeon Master's Manual would not be OK either, since Dungeon Master is PIed too. You could do, however, a Game Master's Handbook.)