What does "Powered by GURPS" mean? What's the difference between a PBG title and a regular GURPS book?
There are several differences, but none of them is hard and fast. The only thing we can say for sure about all the PBG books is that they're compatible with GURPS. But in general:
Powered By GURPS Releases . . . So Far
These are the PBG lines that are already available or announced. Each title links to the page for the book or line.
Discworld Roleplaying Game
The official roleplaying version of Terry Pratchett's best-selling fantasy series. (The first printing didn't say Powered By GURPS, because we hadn't thought of the phrase yet . . . but Discworld Roleplaying Game was where we came up with the concept for this kind of book.)
Soon to be updated for GURPS Fourth Edition!
The greatest conflict in human history. The armies, the weapons, the vehicles, the battles.
A near-future, hard-science campaign background, with no aliens except the ones we have created ourselves . . .
GURPS Conspiracy X
Published by Eden Studios, this is a world of alien invaders, supernatural horrors, and soulless conspiracies . . . hiding behind a thin facade of normality . . . Pray this is only a game.
The Hellboy Sourcebook and Roleplaying Game
Mike Mignola's brilliant "Hellboy" comics and graphic novels, adapted for your campaign. Occult horror, intrigue, and monster-bashing as only Mignola's "big red guy" can do it.
GURPS Prime Directive
Published by Amarillo Design Bureau . . . roleplaying in the Star Fleet Universe! This is a long series, starting with the Romulans and Klingons, and going on from there.
The Vorkosigan Saga Sourcebook and Roleplaying Game
The official RPG adaptation of Lois McMaster Bujold's award-winning science-fiction setting.
And more to come . . .