Spartan is a living legend, a veteran of the Alliance Marine Corps, victor of a multitude of military campaigns including the horrific Biomech War. He is both loved and reviled by friend and foe alike, and now lives out on the fringes of the Alliance. He has fought for money, for his people and for the very survival of his species, and lost everything in the process. But when two of his closest friends are captured supplying weapons to the desperate Byotai settlers of Karnak, the fight becomes personal.

In the 20th century Earth sent probes, transmissions, and welcoming messages to the stars. Unfortunately, someone noticed. The Galactics arrived with their battle fleet in 2052. Rather than being exterminated under a barrage of hell-burners, Earth joined their vast Empire. Swearing allegiance to our distant alien overlords wasn't the only requirement for survival. We also had to have something of value to trade, something that neighboring planets would pay their hard-earned credits to buy. As most of the local worlds were too civilized to have a proper army, the only valuable service Earth could provide came in the form of soldiers....

The 26th century. Humanity has expanded beyond Earth’s system to hundreds of planets that colonists now call home. But the United Earth Government and the United Nations Space Command is struggling to control this vast empire. After exhausting all strategies to keep seething colonial insurrections from exploding into a full-blown interplanetary civil war, the UNSC has one last hope.

Nate has a talent for space combat after hundreds of victories in the Star Crusader videogame simulation. His skills are unique, enough to gain him a rare privilege: the chance to join five other Alliance cadets and escape the dull routine of the classroom. They will enter a fierce competition light-years away in the ancient Byotai Empire. Yet days after their arrival a rebellious faction begins a bloody mutiny that spreads like wildfire. The time for competition has ended; the time of war has begun.

Kyle Riggs is snatched by an alien spacecraft sometime after midnight. The ship is testing everyone it catches and murdering the weak. The good news is that Kyle keeps passing tests and staying alive. The bad news is the aliens who sent this ship are the nicest ones out there.

Predator ships stream into human space in unprecedented numbers. The Colonial Marines, controlled by Weyland-Yutani, respond to the incursion, thus entering the Rage War. This terrifying assault by the Yautja cannot go unchallenged, yet the cost of combat is high. Predators are master combatants, and each encounter yields a high body count. Then, when Lt. Johnny Mains and his marines - the VoidLarks - enter the fray, they discover an enemy deadlier than any could imagine.

Jake Price has always dreamed of joining the Darkstream military like his father before him. When he’s told his gaming scores are good enough to qualify him for a brand-new training program designed to find recruits talented enough to pilot humanity’s first mechs, he can hardly believe it. There are hundreds of other recruits competing for the same eight jobs, and they’re all as skilled as he is. But Jake refuses to give up, because humanity is facing its greatest threat yet. If someone doesn’t step up, it could all be over for the human species. Contains the complete series.

James Cook was a gamer headed for the biggest gaming match on Earth. Instead the Planetary Defense Force kidnapped him, his team and 20,000 others. Their alien trainers don't care how many of them survive, they only care that they can fight. James Cook was a gamer, but his avatar Salchar, he was a fighter, a leader, and the man the recruits need. James must put his doubts about himself aside, there's no guide to this, no strategy and it's definitely not a game. He will need to become Salchar, with one goal, to protect his people.

After seven long years of conflict, the Horus Heresy nears its end. But now, as the Warmaster Horus marches on Terra to rip his father from the Throne, the seat of the arch-traitor’s power lies empty. Cthonia, a world once dominated by brutal murder-gangs, is occupied by the Emperor’s praetorians—the indomitable Imperial Fists. For the Sons of Horus, this outrage demands a reckoning.

Captain Mitchell "Ares" Williams is a space marine and the hero of the Battle for Liberty whose shot heard 'round the universe saved the planet from a nearly unstoppable war machine. He's handsome, charismatic, and the perfect poster boy to help the military drive enlistment. Pulled from the war and thrown into the spotlight, he's as efficient at charming the media and bedding beautiful celebrities as he was at shooting down enemy starfighters.

Now, shattered and stuck behind enemy lines, the remnants of Alpha Company struggle to survive. Between them and escape stand three Planetstriders, thousand-meter monstrosities capable of destroying an orbiting capital ship. In order to survive, they must disable these titanic war machines, an impossible task made even more difficult by the discovery of a terrible secret - one that must reach fleet command, no matter the cost.

Imprisoned for a murder he didn’t commit, Kaiden’s only hope of early release is in serving as a Warden in the game-world of Nova Online. Playing as a unique class while surrounded by aliens, pirates and warring guilds, he and his squad are tasked with protecting new players and enforcing the rule of law. But Kaiden has other ideas; he is intent on proving his innocence. The keys to his freedom lie hidden in the game’s seedy underbelly. And as he’ll soon discover, the bloody trail that led to his arrest is more twisted than he could have ever imagined.

Captain Warden and Lance Corporal Goodwin are the space marines with the hard job. They have to infiltrate a Deathless base, identify and capture a senior officer and extract him from under the nose of his soldiers, preferably without dying in the process. They’re relying on Ten to watch their backs, but when he is accosted by the denizens of the jungle he’s yomping through, he has to make a tough choice between speed and humanity.

Heir to one of the leading "Four Horsemen" mercenary companies, Jim Cartwright is having a bad year. Having failed his high school VOWS tests, he's just learned his mother bankrupted the family company before disappearing, robbing him of his Cavalier birthright. But the Horsemen of eras past were smart - they left a legacy of equipment Jim can use to complete the next contract and resurrect the company.

Former Marine Arthur Holland’s destiny begins when an aircraft crashes on his property in the mountains of Colorado. He moves to investigate and to help any survivors, but the closer he gets the less control he has of his movements. An unknown force urges him to open the door of the mysterious craft, discovering the secret that lies within: a dead, alien pilot and a peculiar, otherworldly crystal. If that wasn’t enough, the crystal feels like it is alive. That’s when he hears a single word inside his mind: run.