Ender's Game

When humanity is under threat from an alien race, Ender Wiggin, at the age of six, leaves his family on Earth to journey to the Belt. There he enters Battle School, where his life is strictly disciplined by mind games and computer mock-battles fought in deadly earnest. Instinct, compassion and genius make Ender unequalled. But while he trains, the invasion approaches fast. And Ender will be pushed to the limits of endurance, for he is a unique destiny...