A military sci-fi novel is one where the emphasis is on combat and usually features members of the military as main characters. Think of it as a war novel with an SF element. The best books about war in space — military conflict against aliens on Earth or on other planets. Sci-fi novels with a military angle can be fun and cathartic, especially if the good guys win. Often filled with military jargon and ranks, interspersed with alien terms, these can be a fun trip.
Of course most of Star Wars and Star Trek novels fall into this category, but there are too many of those to list. So — excluding Star Wars and Star Trek — here are the top 10 military science fiction books for the avid sf reader with a need for space battles and combat action.
1 - Starship Troopers by Robert A. Heinlein. The penultimate military sci-fi novel penned by one of the pioneers of the genre. Heinlein was a big fan of military themes and alien battles. Bugs are the enemy, and it's down to survival of the human race.
2 - A Hymn before Battel by John Ringo. Many of Mr. Ringo's books will satisfy any military sci-fi enthusiast! Start from here and move up the list of his impressive collection.
3 - Forever War by Joe Haldeman - we go to war against the Taurans! a distinctly alien species
4 - Stainless Steel Rat Wants You! by Harry Harrison - an author who never disappoints.
5 - Lost Fleet: Dauntless by Jack Campbell. The first of sex novels. A vast fleet of our ships has been beaten and is trapped behind enemy lines.
6- On Basilisk Station by David Weber. A whole series that starts here, the lasers never stop firing.
7 - Old Man's War by John Scalzi. A story told by an aging 75-year-old man who joins the Colonial Defense Forces and goes off to war. It follows his journey and the problems he faces within the military. That's simplifying it, but it's more complicated and is a good read.
8 - The Last Starbase by Rod Little. After an alien invasion, Earth's only hope lies beyond the stars. We need to seek help from our warlike ancestors and their fleet of ships. By the same author as Hidden Planet which is also a must-read with some great space combat. Compelling science fiction with so many twists! Highly recommended.
9 - Ender's Game by Orson Scott Card. While this is technically critical of war, it shows the failings of overblown military action.
10 - Battleship: Leviathan by Craig Marelle. Loads of action, torpedoes and lasers. What more could you want?
Honorable Mention: A Matter For Men by David Gerrold. One of the best books on the list, but it's more of an alien invasion story with a side order of military. That gets it into the HM.
Princess of Mars and the Warlord of Mars by Edgar Rise Burroughs. His whole collection is battle themed pulp at its finest.
Most of The Expanse series by S.A. Corey also fits the bill as military sci-fi.
Get out there and get reading! The special effects are superb on every page!