Ender Wiggin is a very unusual boy -- he's a brilliant tactician, a genius, and a despised "third" in a future that only allows two children. He's also six years old. 
 And despite the fact that Orson Scott Card's sci-fi classic is about a little boy learning how to be a warrior, "Ender's Game" is a pretty gripping and sometimes grim adventure story. The descriptions of children being taught out how to be cold-blooded warriors is pretty creepy, but the well-developed future world that Card comes up with is pretty awesome. 
 After a fight with a gang of bullies, Ender Wiggin is approached by an army officer who wants him to join the elite Battleschool, where kid geniuses become soldiers -- basically because aliens are about to attack Earth AGAIN and may end up wiping out the human race. His brother Peter is too wild and cruel, and his beloved sister Valentine is too mild-mannered. 
 Ender accepts, and quickly finds himself in a dog-eat-dog space school where he soon becomes loathed for the special treatment the teachers occasionally give him -- when they aren't observing his every move. And it soon becomes obvious that Ender has a natural ability that exceeds that of most of the Battleschool recruits: he instinctively knows how to outmaneuver his opponents and protect himself in a fight, even if he annoys some of the "army" commanders who don't like being outshone. 
 Back on Earth, his brother and sister try to alter the increasingly unstable politics of Earth by subtle manipulation of the public, a situation that may bring the ruthless Peter into greater power. And as Ender reaches the end of his training, he faces both the buggers and the knowledge of what he is capable of. 
 "Ender's Game" is kind of an unusual space opera, because the actual war between humans and buggers is not front-and-center until the last act of the story. Up until then, it's about following Ender and his equally unusual siblings as they develop prematurely into adulthood -- these are genius kids who can reshape entire worlds, but you're not really sure that they SHOULD. 
 Card writes in a detailed but brisk style, with pretty realistic dialogue and some ugly dark spots (the description of Peter flaying a squirrel... for no reason). Ender's time at Battle School and Command School feel rather slow at times, only for things to blossom in the final laps of the novel -- Card suddenly turns all our feelings and expectations on their heads. The tragedy of children turned into soldiers becomes even more tragic as we discover what the war is actually all about. 
 As you'd expect from Fascist Hogwarts In Space, there are a lot of kids at Battle School who are developed to certain degrees. But the center of the story is Ender himself -- and despite being a tactical genius with loads of natural ability, Ender never seems like a Wesley Crusher. Like a boy destined to be a Spartan warrior, his inborn skills are what will keep him from ever finding peace. His childhood is sacrificed for war. 
 The other part of the story rests on Peter and Valentine -- Valentine is too nice, while Peter is gradually revealed to be a ruthless genius who works anything and anyone for his goals, which may or may not be self-serving. It's oddly fun to see the growing influence of "Demosthenes" and "Locke" on the cruel government. 
 "Ender's Game" is an intelligent, gripping space opera with an undercurrent of intense tragedy -- it's kind of slow at times, but the strong writing and intriguing main trio keep it afloat.