Book 6: World Builder adds to the D100 Dungeon game a way to create and explore new and fascinating worlds. Your adventurer will travel the lands and interact with towns and cities, and explore a vast wilderness in search of adventure. They will find quests and side quests and may have events sprung on them as they explore. You have explored below, now its time to explore the above. You will need the D100 Dungeon rule book to use this book. - from the publisher's blurb