This 336-page hardcover compiles all the major aspects of the rules in one place. It includes rules for multiple settings, such as Zone Mortalis, Sector Mechanicus, or Ash Wastes battlefields. The book also includes the core rules for fighters, vehicles, plus skills, weapons, traits, and a combined trading post. Additionally, it has rules for the Dominion Campaign and 11 scenarios as well as all the FAQs and Errata from previous books.
Games Workshop released Necromunda: Ash Wastes last year (see "'Necromunda' out of the Hive").