If you're happy with a .pdf file, a google search will turn up some available for download (some that collect a nominal proper fee for the copyright, and errrr some that don't :o).
I haven't opened mine in a long time, soooo out of date for drops and spoils.
The maps are correct for shape, but the spawns may have changed.
Please do not pay $20 for a completely outdated book. That just makes me cringe. Have you tried the fan websites? Stratics (http://lineage2.stratics.com/content/maps/) for instance, has the world maps, a couple of town maps and several necro/catacomb maps. Warcry (http://lineage.warcry.com/index.php/content/maps/maps.php) has some detailed (and cool looking) town maps, as well as all the newbie dungeon maps. And I'm sure if you dug around a bit on other sites you could find maps of the other dungeons.
Basically all that's missing just from those two links I gave you are the older major dungeons, like CT and DVC and the slightly newer dungeons like TOI and GOE. But I doubt TOI is even in the Prima guide, because it wasn't introduced into the game until later, plus it's a pretty basic layout. GOE I know wouldn't be in there and again, it's an easy layout to learn. You probably won't be running into DVC by yourself. So that leaves Cruma - I wouldn't pay $20 just for that one map. I think many old-timers could draw you a crude map of cruma from memory if you're that desperate. I know I could.