Book 1

Terms of Enlistment

by Marko Kloos

Published 28 January 2014
“There is nobody who does [military SF] better than Marko Kloos. His Frontlines series is a worthy successor to such classics as Starship Troopers, The Forever War, and We All Died at Breakaway Station.” —George R. R. Martin

The year is 2108, and the North American Commonwealth is bursting at the seams. For welfare rats like Andrew Grayson, there are only two ways out of the crime-ridden and filthy welfare tenements: You can hope to win the lottery and draw a ticket on a colony ship settling off-world . . . or you can join the service.

With the colony lottery a pipe dream, Andrew chooses to enlist in the armed forces for a shot at real food, a retirement bonus, and maybe a ticket off Earth. But as he starts a career of supposed privilege, he soon learns that the good food and decent health care come at a steep price . . . and that the settled galaxy holds far greater dangers than military bureaucrats or the gangs that rule the slums.

The debut novel from Marko Kloos, Terms of Enlistment is an addition to the great military sci-fi tradition of Robert Heinlein, Joe Haldeman, and John Scalzi.

Book 2

Lines of Departure

by Marko Kloos

Published 28 January 2014
Vicious interstellar conflict with an indestructible alien species. Bloody civil war over the last habitable zones of the cosmos. Political unrest, militaristic police forces, dire threats to the Solar System…

Humanity is on the ropes, and after years of fighting a two-front war with losing odds, so is North American Defense Corps officer Andrew Grayson. He dreams of dropping out of the service one day, alongside his pilot girlfriend, but as warfare consumes entire planets and conditions on Earth deteriorate, he wonders if there will be anywhere left for them to go.

After surviving a disastrous space-borne assault, Grayson is reassigned to a ship bound for a distant colony—and packed with malcontents and troublemakers. His most dangerous battle has just begun.

In this sequel to the bestselling Terms of Enlistment, a weary soldier must fight to prevent the downfall of his species…or bear witness to humanity’s last, fleeting breaths.

Book 3

Angles of Attack

by Marko Kloos

Published 21 April 2015
The alien forces known as the Lankies are gathering on the solar system’s edge, consolidating their conquest of Mars and setting their sights on Earth. The far-off colony of New Svalbard, cut off from the rest of the galaxy by the Lanky blockade, teeters on the verge of starvation and collapse. The forces of the two Earth alliances have won minor skirmishes but are in danger of losing the war. For battle-weary staff sergeant Andrew Grayson and the ragged forces of the North American Commonwealth, the fight for survival is entering a catastrophic new phase.

Forging an uneasy alliance with their Sino-Russian enemies, the NAC launches a hybrid task force on a long shot: a stealth mission to breach the Lanky blockade and reestablish supply lines with Earth. Plunging into combat against a merciless alien species that outguns, outmaneuvers, and outfights them at every turn, Andrew and his fellow troopers could end up cornered on their home turf, with no way out and no hope for reinforcement. And this time, the struggle for humanity’s future can only end in either victory or annihilation.

Book 4

Chains of Command

by Marko Kloos

Published 19 April 2016

The assault on Earth was thwarted by the destruction of the aliens’ seed ship, but with Mars still under Lanky control, survivors work frantically to rebuild fighting capacity and shore up planetary defenses. Platoon sergeant Andrew Grayson must crash-course train new volunteers—all while dulling his searing memories of battle with alcohol and meds.

Knowing Earth’s uneasy respite won’t last, the North American Commonwealth and its Sino-Russian allies hurtle toward two dangerous options: hit the Lanky forces on Mars or go after deserters who stole a fleet of invaluable warships critical to winning the war. Assigned to a small special ops recon mission to scout out the renegades’ stronghold on a distant moon, Grayson and his wife, dropship pilot Halley, again find themselves headed for the crucible of combat—and a shattering new campaign in the war for humanity’s future.


Book 5

Fields of Fire

by Marko Kloos

Published 28 February 2017

The time has come to take the fight to the Lankies.

Mars has been under Lanky control for more than a year. Since then, the depleted forces of Earth’s alliances have rebuilt their fleets, staffing old warships with freshly trained troops. Torn between the need to beat the Lankies to the punch and taking enough time to put together an effective fighting force, command has decided to strike now.

Once again, seasoned veterans Andrew and Halley find themselves in charge of green troops and at the sharp tip of the spear as the combined military might of Earth goes up against the Lankies. But if there’s one constant in war, it’s that no battle plan survives first contact with the enemy…and the Lankies want to hold on to Mars as badly as humanity wants to reclaim it.


Book 6

Points of Impact

by Marko Kloos

Published 9 January 2018

Humankind may have won the battle, but a new threat looms larger than ever before…

Earth’s armed forces have stopped the Lanky advance and chased their ships out of the solar system, but for CDC officer Andrew Grayson, the war feels anything but won. On Mars, the grinding duty of flushing out the twenty-meter-tall alien invaders from their burrows underground is wearing down troops and equipment at an alarming rate. And for the remaining extrasolar colonies, the threat of a Lanky attack is ever present.

Earth’s game changer? New advanced ships and weapons, designed to hunt and kill Lankies and place humanity’s militaries on equal footing with their formidable foes. Andrew and his wife, Halley, both now burdened with command responsibilities and in charge of more lives than just their own, are once again in humanity’s vanguard as they prepare for this new phase in the war. But the Lankies have their own agenda…and in war, the enemy doesn’t usually wait until you are prepared. As Andrew is once again plunged into the chaos and violence of war with an unyielding species, he is forced to confront the toll this endless conflict is taking on them all, and the high price of survival…at any cost.


Book 7

Orders of Battle

by Marko Kloos

Published 8 December 2020

The battle against the Lankies has been won. Earth seems safe. Peacetime military? Not on your life.

It’s been four years since Earth threw its full military prowess against the Lanky incursion. Humanity has been yanked back from the abyss of extinction. The solar system is at peace. For now.

The future for Major Andrew Grayson of the Commonwealth Defense Corps and his wife, Halley? Flying desk duty on the front. No more nightmares of monstrous things. No more traumas to the mind and body. But when an offer comes down from above, Andrew has to make a choice: continue pushing papers into retirement, or jump right back into the fight? What’s a podhead to do?

The remaining Lankies may have retreated in fear, but the threat isn’t over. They need to be wiped out for good before they strike again. That’ll take a new offensive deployment. Aboard an Avenger warship, Andrew and the special tactics team under his command embark on the ultimate search-and-destroy mission. This time, it’ll be on Lanky turf.

No big heroics. No unnecessary risks. Just a swift hit-and-run raid in the hostile Capella system. Blow the alien seed ships into oblivion and get the hell back to Earth. At least, that’s the objective. But when does anything in war go according to plan?


Book 8

Centers of Gravity

by Marko Kloos

Published 30 August 2022

Stranded light-years from home, Major Andrew Grayson and his crew are on a desperate mission to discover the Lankies’ secrets. They can’t let what they’ve found die with them.

Nine hundred light-years from home, Major Andrew Grayson and the crew of NACS Washington are marooned in a sunless system with limited water, reactor fuel, and food. The last hope for survival is to go where nothing human has gone before.

After embarking on a scouting mission to the only moon with surface signs of life, Andrew and his special tactics team make two startling discoveries. One is a dream: a form of protein and plant life that could save the starving humans in the rogue system. The second is a nightmare: this harvested rock is infested with Lankies. Far from the seemingly mindless aggressors Andrew has battled for years, these show a terrifying awareness, and they have surprising secrets of their own hidden away in the darkness.

When the Lankies sense an uninvited presence in their world, Andrew’s operation becomes an expedition to hell. The odds against his small crew are stacked high. Of all the mysteries of space, how to escape with their lives is the greatest unknown of all.


Frontlines: Requiem

by Marko Kloos

Published 7 September 2016

Lucky Thirteen

by Marko Kloos

Published 1 September 2016

Measures of Absolution

by Marko Kloos

Published 1 September 2016