The disciples of the Machine God, the Cult Mechanicus are on the front line of the Quest for Knowledge. Tech-priests lead their forces of augmented warriors and battle-automata into battle with the Omnissiah's foes in defence of His secrets. Magos-Explorator Omnid Torquora orchestrates war against the Iron Warriors for control of a long-lost forge world.

Belisarius Cawl, Archmagos Dominus of the Adeptus Mechanicus, is the most brilliant mind alive. For 10,000 years he has furthered the cause of mankind, working under the aegis of the Emperor and Lord Commander Roboute Guilliman to prevent the inexorable march of the alien and the traitor. Many call him heretic, but all must recognise the magnitude of his achievements, for who else but he was entrusted to create a new generation of Space Marines?  

On Periremunda, the populace are rioting. With local forces unable to contain the widespread civil disorder, Commissar Cain and his regiment of Valhallans are called in to help. However, it seems there is more to the rebellion than first appeared, and Cain suspects sinister forces at work behind the scenes. When the commissar is reunited with Inquisitor Amberley Vail, it seems his fears are realised. In this the fifth book in the popular Ciaphas Cain series, our hero is thrown into a deadly conspiracy that even he might not be able to emerge from alive.

Once again, reluctant hero Commissar Cain is catapulted into glory in the fourth instalment of this tremendously popular series. Escaping from a disastrous space battle, the commissar and his malodorous sidekick Jurgen crash-land behind enemy lines. Even the sly Cain can't avoid a straight fight this time, as the only way out is to round up what few troops they can find and fight their way back to safety. Unfortunately, hundreds of thousands of barbaric alien orks stand in their way.

Ciaphas Cain's latest mission takes him and his Valhallan regiment to the planet of Adumbria to defend against an approaching Chaos invasion. However, infighting with fellow Imperial Guard regiments from the world of Tallarn, commanded by an old 'friend' of Cain's from the Schola Progenium and the uprising of a sinister cult on the planet puts paid to any hopes of an easy life.

On the battlefields of Aexe Cardinal, the stalwart forces of the Imperial Guard are locked in a deadly stalemate with the dark armies of Chaos. Colonel-Commissar Ibram Gaunt and his regiment, the Tanith First and Only, are thrown headlong into the living hell of trench warfare, where death by an unseen enemy is always just a moment away. The only chance for Gaunt and his lightly armed scouts to survive is to volunteer for a mission so dangerous that no one else dares accept it.

In the darkness beyond the galaxy, there are monsters. Some swim closer to the light, drawn by the beacon that is the Astronomican, while others stalk the Void, predators in the dark. The Carcharodons have hunted for millennia, but now they are drawn into a new blackness...the Dark City of the drukhari itself. Commorragh. For a thousand years, Chaplain Tangata Manu has searched for a relic lost under his watch: an ancient thing, once charged into the keeping of the Forgotten One himself. But at the brink of seeing his hunt fulfilled and the relic returned, it is stolen from under him.

Inquisitor Erasmus Crowl has discovered a terrible plot, its roots firmly planted in the very highest levels of Terra. Pursuing it is fraught with risk, but Crowl’s sense of duty compels him to persevere. He and his acolyte Spinoza run down their leads in secret, knowing that their every move invites danger, but even as they begin to reveal the truth, a greater peril is unfolding in the skies - the Great Rift is becoming manifest. During the madness that threatens to tear Terra asunder, Crowl’s Inquisitorial base of operations comes under attack and is badly ravaged.

On the ice world of Simia Orichalcae a spate of mysterious disappearances is causing unrest amongst the mine workers, and, as senior officer of the Astra Militarum, Commissar Ciaphas Cain is nominated to investigate. Unbeknownst to him, the planet is right in the path of a major ork incursion, and, as the savage greenskins attack, a malevolent evil begins to stir deep in the ice caves. 

Fell times have come to the galaxy. Cadia has fallen, destroyed by the onslaught of Chaos. A Great Rift in the warp has opened, and from its depths spew daemons and the horrors of Old Night. But all hope is not lost… A hero, long absent, has returned, and with him comes the wrath of the Ultramarines reborn. Roboute Guilliman has arisen to lead the Imperium out of darkness on a crusade the likes of which has not been seen since the fabled days of the Emperor. But never before have the forces of Ruin amassed in such numbers, and nowhere is safe from despoliation. 

In the hellish sprawl of Imperial Terra, Ordo Hereticus Inquisitor Erasmus Crowl serves as a stalwart protector, for even the Throneworld is not immune to the predations of its enemies. In the course of his duty, Crowl becomes embroiled in a dark conspiracy, one that leads all the way to the halls of the Imperial Palace. As he plunges deeper into the shadowy underbelly of the many palace districts, his investigation attracts the attention of hidden forces, and soon he and his acolyte Spinoza are being hunted.

In the city of Queen Mab, nothing is quite as it seems. Pariah, spy and Inquisitorial agent Alizebeth Bequin is all of these things and yet none of them. An enigma, even to herself, she is caught between Inquisitors Gregor Eisenhorn and Gideon Ravenor, former allies now enemies who are playing a shadow game against a mysterious and deadly foe. Coveted by the archenemy, pursued by the Inquisition, Bequin becomes embroiled in a dark plot of which she knows not her role or purpose.

In disgrace after a catastrophic war, Colonel-Commissar Ibram Gaunt and the Tanith First are sent to retrieve precious artefacts from a world lost to Chaos. With enemy all around them and time against them, Gaunt's Ghosts and their allies must prevent the holy relics of Saint Sabbat from falling into their foes' hands, and as mysterious events begin to occur, Gaunt begins to suspect that the Saint herself might be aiding them from beyond the grave. 

On an Imperial outpost world on the fringes of tau space, the renowned Commissar Ciaphas Cain and his fractious regiment of Valhallan Guard, newly created from the remnants of two devastated units, find themselves in the middle of a war. As the Astra Militarum struggle to contain worldwide civil insurrection, can the wily Commissar Cain identify the real villain before the planet is lost to the Imperium forever?

The primarch Roboute Guilliman of the Ultramarines has returned in the galaxy’s hour of need, and all muster to his Indomitus Crusade to hold back the darkness. Amongst these heroes is Cato Sicarius, Master of the Watch and vaunted captain of Second Company. Disaster befalls Sicarius and his brave warriors as their ship, the Emperor’s Will, is lost to the hellish warp, its entire crew believed slain. But Sicarius endures, though he and his men are fighting for their very survival against the denizens of the Great Rift - the daemons and renegades of Chaos.