MasterBook

From the introduction in the book:

Masterbook is a master game system published by West End Games. This system can be used to roleplay in virtually any game universe, with virtually any options, but it is also designed to be used with specific game settings designed by West End Games.

Each game WorldBook will provide additional information on each of the new fictional settings, but every MasterBook world follows the core set of rules set down in this volume

Those MasterBook lines that include the full rules are listed as standalone RPGs:

• The World of Bloodshadows
• The World of Indiana Jones
• The World of Necroscope

The remaining MasterBook lines all require the core Masterbook rulebook and so are instead listed as separate settings and each of the relevant books are linked to the MasterBook RPG:

• The World of Aden
• The World of Species
• The World of Tales from the Crypt
• The World of Tank Girl