"In the twentieth century Earth sent probes, transmissions and welcoming messages to the stars. Unfortunately, someone noticed.B. V. Larson's "Steel World" is the hybrid offspring of "Starship Troopers" and John Ringo's "Posleen Wars". It's Heinlein sans the moral messages mixed with Ringo's duplicitous galactics.
"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 we could provide came in the form of soldiers. Someone had to do their dirty work for them, their fighting and dying.
"I, James McGill, was born in 2099 on the fringe of the galaxy. When I ran out of college loans and options I turned to the stars. My first campaign involved the invasion of a mineral-rich planet called Cancri-9, better known as Steel World.
"The attack didn’t go well, and now Earth is in a grim struggle for survival. "
The shtick is that the mercenaries of Earth's Legions can be revived after death: you fight, you die and then you fight again. This is not at all a gimmick, as some reviewers have suggested; it opens the door to interesting plot developments.
This ebook is well-written and highly recommended as an escapist, fun, military-SF page-turner; it's to be hoped Larson writes a sequel.