Robert A. Heinlein's second novel to win the Hugo award: Starship Troopers (1959.) A shorter version (missing at least one battle scene) was serialized in The Magazine of F&SF in 1959 - as "Starship Soldier."

At least once every generation, some Science Ficiton writer takes a serious look at why and how wars are fought, and this can form a sort of dialogue with other authors who have done the same. Heinlein's Starship Troopers and Joe Haldeman's The Forever War both involve wars of humans against aliens, the relationship of the military to the society which creates and supports it, and the use of infantry in Battle Suits as the ultimate way of getting results other than ship-to-ship combat or bombardment from orbit. Each book reflects the author's own experience in the military - with quite different emphasis and results.

I read this as a teen when I found it in the "juvenile" section of my library (even though it is NOT labelled a juvenile, it often gets lumped in.) For a decent plot summary, I'm quoting parts from a 4-page review by my favorite reviewer P. Schuyler Miller - in Astounding March 1960. [Much of the review focused on the idea that we should not mistake a well-written fiction for the author's own views, using Oliver Wiswell as an example]:

(...some day I'll finish this summary)