Cover: The Underworld Sourcebook describes in detail the "Big Four" International criminal syndicates: the Mafia, the Yakuza, the Triads and the Seoulpa Rings. Each syndicate's markets, business practices, traditions, histories and secret rituals are revealed, along with loads of information on gangs, terrorists, assassins and other groups who rule the shadows through no law but their own. The Underworld Sourcebook includes guidelines for building campaigns around organized crime and customizing them for local settings, and alternate campaign rules that allow players to play members of organized-crime syndicates, it provides a wealth of adventure hooks, story starters, background information and rules for use in any Shadowrun campaign. For use with Shadowrun and the Shadowrun Companion: Beyond the Shadows.