Heinlein was the dean of Science Fiction writers, dominating the Golden Age and remaining enormously influential even today. Starship Troopers is his most controversial work, and perhaps his greatest.
The story follows Johnnie Rico, a soldier of the 'Mobile Infantry'- sort of a juiced-up Marine Corps with portable nukes and bad-ass combat armor. As Johnnie matures in the service, we learn surprising things about the world he lives in and the government he serves.
It has been derided as "Heinlein's Utopia", and I was surprised by the scorn heaped upon it by his contemporaries. Heinlein describes a society in which only veterans are allowed to vote, where public floggings are common and Moral Philosophy is a required school course. He supports these positions with impeccable logic and masterful storytelling.
"Masterful storytelling" refers, in this case, to the writing and construction of the book - sadly, Johnnie's story doesn't have a real ending, it just sort of winds down amid the continuing war. This may be on purpose - the war will go on and so will Johnnie Rico - but it feels rather abrupt.
The best parts of Starship Troopers are the explanations of theory, of Heinlein's opinions of society and how he thought it could be improved. It can be fairly argued that the entire book is an excuse for the expository speeches, but the whole thing works. (Troopers was published just a couple years after Atlas Shrugged, and the contrast is stark - the difference being that Heinlein can write.)
Juicy red meat for libertarians, and real lessons waiting to be learned for citizens.