Starship Troopers

There is little plot but there is character development in the form of Johnnie Rico going from impulsive deciding to join the military, to choosing it as a life career to leading a platoon in a battle.

It is not my thing, as I find the endless military procedure, details, structure, etc. very boring. Yes, there's aliens, spaceships, and fantastic technology, but the science fiction seems almost superfluous here.

Heinlein had a fun, easygoing writing style so it's not as dry of a read as making it out to be.

Superficially it appears to be a celebration of military, war, and discipline but there is a more important point that he was getting to, one of responsibility to the group (family, colleagues, fellow citizens of where you live, etc.) as opposed to focusing on yourself as an individual.

“Under our system every voter and officeholder is a man who has demonstrated through voluntary and difficult service that he places the welfare of the group ahead of personal advantage.”

Violence is horrifying and should be a last resort, but I think Heinlein was emphasizing the notion of making sacrifices to a greater good rather than glorifying war.