The Horus Heresy: Book One - Betrayal (Forge World Series) - Contents: The following is every section contained within The Horus Heresy Book One - Betrayal:Preface - The preface of this book, and all other Forge World Horus Heresy books to follow begin with a foreword by the in-universe "author" of the book, an unknown individual who signs with the letters AK.Imperialis Dominatus - A Great Crusade-era map that covers two full pages, and includes the names of many notable planets and locations.Age of the Emperor - A short retelling of the history of the Imperium of Man up to the end of the Great Crusade. This includes the Age of Strife, the Unification Wars, the Treaty of Mars, the later Great Crusade and Horus' fall. Also included is information regarding the Primarchs, the Warp and Navigators, the Astra Telepathica and Psykers, the Astronomican, basic Space Marine armour and weapons, and the High Lords of Terra.The Legiones Astartes - This section contains information regarding the twenty Space Marine Legions including their origins, Space Marine initiation and organ implantation processes, and their role within the Imperium.Crusade Legion Disposition - A two page layout of a basic Space Marine Legion command structure and strategic disposition along with other additional information.The Death of Isstvan III - This section describes the Isstvan System, its initial Imperial Compliance and rebellion, the Battle of Isstvan III and the Istvaan III Atrocity from the Loyalists' planetfall to the Traitor Legions' Virus Bombardment of Istvaan III's surface.Part 1: TreacheryPart 2: RuinPart 3: ExterminationThe Space Marine Legions - This section contains an in-depth look at the history of the four Space Marine Legions involved in the Istvaan III Atrocity: The Sons of Horus, the World Eaters, the Emperor's Children, and the Death Guard, as well as the Legio Mortis Titan Legion.The Sons of HorusThe World EatersThe Emperor's ChildrenThe Death GuardThe Legio MortisThe Death of Isstvan III Campaign - This section describes a six-mission campaign for reenacting the Istvaan III Atrocity on the tabletop and three "legendary battles" and terrain information.The Death of Isstvan III CampaignCampaign PhasesIsstvan III Battle MissionsDeployment MapsMission 1: Blood FuedMission 2: Fire TideMission 3: Shatter StrikeMission 4: OnslaughtMission 5: DominionMission 6: Extermination'Cometh the Red Angel''The Flight of Truth''The Death of Gods and Angels'Isstvan III Battlefield TerrainCampaign Appendix: Zone Mortalis - This section contains the rules necessary for a Zone Mortalis battleground, which is fighting in confined spaces such as starships, underground areas, and narrow urban environments.Campaign Appendix: Zone MortalisZone Mortalis Assault MissionZone Mortalis Encounter MissionIsstvan III Zone Mortalis StratagemsAge of Darkness Battles - This section contains the rules necessary for a Space Marine Legion army list that is set in the late Great Crusade and early Horus Heresy eras. It includes force organisation charts, an allies matrix, units, armour, and wargear available to the Legiones Astartes in general.Age of Darkness BattlesAge of Darkness Allies ChartSpace Marine Crusade Legion Army List - This section contains the rules for the various units used by the Space Marines Legions during the Istvaan III Atrocity.Space Marine Legion Warlord TraitsHeadquartersElitesTroopsDedicated TransportsFast AttackHeavy SupportLords of WarSpace Marine Legion WargearSpace Marine Crusade Legion Appendix - This section contains the rules, Legion-specific units, and special characters for the four Legions the took part in the Istvaan III Atrocity.The Sons of HorusThe World EatersThe Emperor's ChildrenThe Death GuardMechanicum Army List Appendix - This section contains the rules and units nessecary for building an Mechanicum allied force for a Legiones Astartes army.Mechanicum Army List AppendixLords of WarCalleb DecimaApocalypse Rules Appendix - This sections contains a condensed reference of the rules nessecary for a Warhammer 40,000 Apocalypse game.Appendix I: Super-Heavy VehiclesAppendix II: Gargantuan CreaturesAppendix III: Super-Heavy FlyersAppendix IV: Additional Special RulesNew Special Rules Summery - This section summarises various special rules found within the book, and also includes the four different versions of the 'Legiones Astartes' rule used by the four Legion features in the book.Afterword - An afterword about the Horus Heresy and Warhammer 40,000 by the book's real-world author, Alan Bligh.