Starship Troopers is a military science fiction novel written by Robert A. Heinlein. It is set in a future where humanity is engaged in a war against an insectoid alien species known as the Arachnids. The story follows Juan Rico, a young recruit who joins the Mobile Infantry and fights in various battles across the galaxy. Starship Troopers explores themes of militarism, citizenship, and the nature of war. It is a thrilling and action-packed book that has become a classic of the genre.