The Adeptus Mechanicus are fervent worshippers of the Machine God on Mars. For millennia, the hooded priests of the Machine Cult have overseen the creation, upkeep, and protection of Humanity's remaining technological marvels with deep respect and ceremonial rites. Guided by Tech-Priests whose frail organic bodies have been replaced by mechanical enhancements, their armies defend forge worlds and venture across the galaxy in search of ancient archeotech.

Within the ranks of the Machine Cult are legions of obedient cybernetic soldiers, massive combat robots, and battle servitors. Armed with a variety of obscure weapons, they can obliterate enemies with radioactive salvos or immolate them with torrents of blazing energy. Those who attempt to disrupt the sacred works of the Omnissiah must confront the formidable force of this ruthless mechanical war engine, devoid of mercy or regret.

Codex: Adeptus Mechanicus serves as an indispensable manual for collecting and playing with the Adeptus Mechanicus faction. It provides the essential rules for fielding an Adeptus Mechanicus army in Warhammer 40,000 games, encompassing narrative Crusade campaigns and Combat Patrol skirmishes. Additionally, it offers extensive insights into their enigmatic techno-beliefs, peculiar cybernetics, prominent forge worlds, and their role within the Imperium.

Contained within this 120-page hardcover are:
- Detailed background on the Adeptus Mechanicus, tracing the ancient origins of the Machine Cult and the customs of forge worlds scattered across the galaxy
- Artwork that vividly captures the mechanical allure, unusual cyborg forms, and vast scope of the Adeptus Mechanicus
- 30 datasheets outlining the characteristics, equipment, and special abilities of every Adeptus Mechanicus unit, from the ominous Sydonian Dragoons to Belisarius Cawl himself
- Five themed Detachments like the Explorator Maniple and Cohort Cybernetica, each with its own distinct rules
- Crusade rules for pursuing lost archeotech and reconstructing ancient machine relics to enhance your leaders
- Standalone Combat Patrol rules and a painting guide, enabling swift gameplay with units like the Purge Corps Deltic-9
- An 'Eavy Metal showcase of exquisitely painted Citadel miniatures, featuring a variety of forge worlds

This volume also includes a single-use code to unlock Codex: Adeptus Mechanicus content in the Warhammer 40,000: The App.