d20 Past, softback sourcebook for d20 Modern, by James Wyatt and Gwendolyn F.M. Kestrel
“Dash down the gaslit streets of Victorian horror or ride the dusty trails of the Wild West. Board the tall ships of the Spanish Main or raid the trenches of the Great War. In d20 Past, heroes can find excitement in any historical era from the renaissance to World War II. Whether period-specific or pulp-flavored, the possibilities for adventure in the world of yesteryear are endless.
To use this product, you also need the d20 MODERN Roleplaying Game core rulebook. For players and Gamemasters, this product is compatible with other d20 System roleplaying games.”