From the website:
"It Happened Otherwise!Travel the Confederate States of America by dirigible. Battle the Aztec Jaguar Knights in their conquest of Europe. Join the American Resistance against Nazi occupation. March with the Roman legions on their campaigns in the New World. GURPS Alternate Earths provides fully fleshed-out backgrounds for six worlds to be used with a GURPS Time Travel "Infinite Worlds" campaign, or in conjunction with many other GURPS worldbooks.
GURPS Alternate Earths includes:
- Complete histories, including timelines, for each Alternate Earth.
- Gadgets that were never invented – but should have been!
- A plethora of new character types, from the Confederate Cavalier to the Cyber-Samurai.
- The Smugglers' Guide to Interdimensional Trade.
- Subversive plots by the nefarious Centrum.
- Guidelines for creating your own parallel Earths.