HeroQuest Glorantha RPG - Rules of Play says:
The book includes everything you need to have to start a campaign in Glorantha: basic overview of the setting; character creation; magic rules for spirit magic, rune magic, sorcery, and Lunar magic; seven complete cult write ups; heroquesting rules and explanations; monster descriptions; themes of Glorantha; and even an introductory adventure that will take your heroes on a heroquest into the Underworld!