While (often referred to as "GURPS Classic" by its publisher) has been superseded by the 4th Edition, a significant portion of its library is officially available in digital eBook formats. Current Availability & Digital Distribution
A PDF guide for converting 3rd Edition characters and sourcebook information to the current 4th Edition rules. GURPS 3rd Edition eBooks
The GURPS Basic Set, Third Edition, Revised is available as a fully indexed PDF for approximately $20.00. While (often referred to as "GURPS Classic" by
Steve Jackson Games (SJG) maintains a massive digital catalog of 3rd Edition materials, primarily through their Warehouse 23 storefront and DriveThruRPG . GURPS 3rd Edition eBooks