Did you know that there is an official Discover Sci-Fi Facebook group?

Fuelled by the opinions of thousands of sci-fi fans like yourself, each week we spark a new debate where you guys battle it out over which books rank at the top of best ever lists.

Ordered from 10 to 1 below based on your votes in the group and on this blog, this week we've got your top 10 selections for the best military sci-fi book/series of all time.

Click on the links to pick up each of these top picks to add to your collection, and then add your comments at the bottom of this post (or in our Facebook group) to let us know if you agree (or not!).

Want to see who didn't make the cut? Click here to view the original poll that inspired this list.

*The results were decided by you based on votes tallied up between our Facebook group and on our blog.

10. Hell Divers by Nicholas Sansbury Smith

Rounding out the top 10 list is the New York Times and USA Today bestselling Hell Divers series by Nicholas Sansbury Smith. In Hell Divers, Smith unleashes post-apocalyptic science-fiction with the pacing of a thriller. He achieves his world-building succinctly, and moves from thrills to chills without the story becoming a mere catalogue of violence, along with tender moments that round out the characters. Hell Divers offers genre fans everything they could ask for, from fresh takes on the post-apocalypse to social commentary reminiscent of Snowpiercer, and plenty of action. The book's swift, tight plotting will also appeal to thriller fans, with a cliffhanger ending that leaves readers suspended mid-air for the rest of a promised trilogy.

9. The Ember War Series by Richard Fox

At number 9, The Ember War by Richard Fox is a 9 book series that can be described as “Battlestar Galactica meets Mass Effect.” It is a story of first contact with galactic empires, some with our best interests at heart, others that see us as an infestation to be wiped out. Epic space battles, heroes and villains you'll never forget and just the right amount of humor to make you bust out laughing while you're reading in public.

8. Bobiverse by Dennis E. Taylor

Bobiverse by Dennis E. Taylor is the story of Robert “Bob” Johansson, who, after becoming financially independent by selling his software company, decides to spend some of his money by contracting to have his head cryogenically frozen by CryoEterna Inc. upon his death. The idea is that his head would be preserved until later, when technology permitted a body to be grown and his thawed head attached to it – thus resuming life. The next day he is unexpectedly killed in an automobile accident, and his contract is activated. He wakes up 117 years later and finds that he has been harvested from his frozen disembodied head and installed in a computer matrix as an artificial intelligence. The world has significantly changed.

7. The Lost Fleet by Jack Campbell

Coming in at number 7, is The Lost Fleet by “Jack Campbell,” which is the pseudonym for John G. Hemry, a retired Naval officer (and graduate of the U.S. Naval Academy in Annapolis). As Jack Campbell, he writes The Lost Fleet series of military science fiction novels.

From book 1… Captain John “Black Jack” Geary’s legendary exploits are known to every schoolchild. Revered for his heroic “last stand” in the early days of the war, he was presumed dead. But a century later, Geary miraculously returns from survival hibernation and reluctantly takes command of the Alliance Fleet as it faces annihilation by the Syndic.

Appalled by the hero-worship around him, Geary is nevertheless a man who will do his duty. And he knows that bringing the stolen Syndic hypernet key safely home is the Alliance’s one chance to win the war. But to do that, Geary will have to live up to the impossibly heroic “Black Jack” legend..

6. Old Man's War by John Scalzi

In your #6 pick, Scalzi's blending of wry humor and futuristic warfare recalls Joe Haldeman's classic, The Forever War (1974), and strikes the right fan–pleasing chords to probably garner major sf award nominations.

In Old Man's War…with his wife dead and buried, and life nearly over at 75, John Perry takes the only logical course of action left him: he joins the army. Now better known as the Colonial Defense Force (CDF), Perry's service-of-choice has extended its reach into interstellar space to pave the way for human colonization of other planets while fending off marauding aliens. The CDF has a trick up its sleeve that makes enlistment especially enticing for seniors: the promise of restoring youth. After bonding with a group of fellow recruits who dub their clique the Old Farts, Perry finds himself in a new body crafted from his original DNA and upgraded for battle, including fast-clotting “smartblood” and a brain-implanted personal computer. All too quickly the Old Farts are separated, and Perry fights for his life on various alien-infested battlegrounds.

5. Ender's Game by Orson Scott Card

Ender's Game by Orson Scott Card is the winner of the 1985 Nebula Award for Best Novel and the 1986 Hugo Award for Best Novel. This futuristic tale involves aliens, political discourse on the Internet, sophisticated computer games, and an orbiting battle station. Yet the reason it rings true for so many is that it is first and foremost a tale of humanity; a tale of a boy struggling to grow up into someone he can respect while living in an environment stripped of choices. Ender's Game is a must-read book for science fiction lovers, and a key conversion read for their friends who “don't read science fiction.”

*Ender's Game placed at #6 on our list of best sci-fi film adaptations.

*Andrew “Ender” Wiggin placed at #7 on our list of most epic sci-fi characters.

4. Dune by Frank Herbert

At #4 is fan-favorite Dune by Frank Herbert – a book that's shown up in almost all of the top 10 lists we publish. A stunning blend of adventure and mysticism, environmentalism and politics, Dune won the first Nebula Award, shared the Hugo Award, and formed the basis of what is undoubtedly the grandest epic in science fiction.

*Dune came in at #3 on our list of best sci-fi film adaptations.

*The book's protaganist Paul Atreides came in at #3 on our list of most epic sci-fi characters.

*The Bene Gesserit Sisterhood and Baron Vladimir Harkonnen both placed on our list of most epic villains of all time.

3. Galaxy's Edge Series by Jason Anspach and Nick Cole

Galaxy's Edge is a co-written project by Jason Anspach and Nick Cole. Each book in the Galaxy's Edge series is an essential piece of an interconnected whole. Fight alongside Lieutenant Chhun and Victory Company through the deserts of Kublar in Legionnaire. Join the roguish Captain Keel and notorious bounty hunter Tyrus Rechs as they chase the same target in Galactic Outlaws. Continue to Kill Team to see how all these characters find their place on the galactic stage together, along with Legion Commander Keller, Dark Ops, and the mysterious secret agent X… then brace for a civil war initiated by the enigmatic Goth Sullus in Attack of Shadows.And that's only the beginning.

2. Starship Troopers by Robert A. Heinlein

At number 2 comes the cult classic Starship Troopers by Robert A. Heinlein. This controversial Hugo Award-winning bestseller, a recruit of the future goes through the toughest boot camp in the Universe—and into battle against mankind’s most alarming enemy…

“A classic…If you want a great military adventure, this one is for you.”—All SciFi

*Starship Troopers also placed in our top 10 list of best sci-fi books of all time. Click here to check out the full list.

1. The ExForce Series by Craig Alanson

Craig Alanson is a New York Times best-selling author of the (currently) 7 book Expeditionary Force (ExForce) series. His first audiobook Columbus Day, ExForce book 1, was one of five finalists for Audiobook Of The Year 2018.

And his fans came out in droves in support of his massively successful military sci-fi series, rocketing it to the very top of this exciting debate!

From book 1… We were fighting on the wrong side, of a war we couldn't win. And that was the good news.

The Ruhar hit us on Columbus Day. There we were, innocently drifting along the cosmos on our little blue marble, like the native Americans in 1492. Over the horizon come ships of a technologically advanced, aggressive culture, and BAM! There go the good old days, when humans only got killed by each other. So, Columbus Day. It fits.

When the morning sky twinkled again, this time with Kristang starships jumping in to hammer the Ruhar, we thought we were saved. The UN Expeditionary Force hitched a ride on Kristang ships to fight the Ruhar, wherever our new allies thought we could be useful. So, I went from fighting with the US Army in Nigeria, to fighting in space. It was lies, all of it. We shouldn't even be fighting the Ruhar, they aren't our enemy, our allies are.

I'd better start at the beginning….

Well, what do you think of that list? Do you agree, or do you feel as though your most-loved military sci-fi book/series is missing/didn't place as you think it deserved? Feel free to join us here in our Facebook group to chime in on the debate, and then check out our most recent poll while you're there. Don't have Facebook? Feel free to add to the comments below.

*All book-related copy in this post was pulled from Amazon & Wikipedia.