Goodman Games - The Complete Guide to Doppelgangers

From the Back of the Book:

"What if everyone around you were a doppelganger... and only you didn't know?
The Complete Guide to Doppelgangers is a stand-alone, world-neutral sourcebook covering everything you ever wanted to know about doppelgangers. It includes:

• The true origin of these bizarre creatures.
• Background on doppelganger social structure, including their various life stages and their relationship to mimics.
• Details on how the doppelgangers have penetrated human society.
• New feats and skills for doppelgangers, plus the dreaded Protean Warrior class.
• Unique campaign ideas centered around doppelgangers.
• New monster stats for intriguing variations on the standard doppelganger.
• Supplemental material online."