Ender's Game (Ender's Saga 1)

The most famous novel of modern science fiction: an undisputed classic, winner of the Hugo, Nebula, and SF Chronicle awards.

Earth is threatened by an alien race, the Formics, who communicate telepathically and believe they have nothing in common with humans, whom they intend to destroy.

To defeat them, a new kind of military genius is needed, and for this reason, Ender's birth has been permitted, which is, in a way, an anomaly, as he is the third child of a couple in a world that has strictly limited the number of descendants to two.

The child Ender must learn everything related to war through video games and dangerous simulated space battles he conducts with his peers.

In this book, Orson Scott Card's characteristic skill in handling emotions is combined with an interest in the use of computer simulations and fantasy games in the military, strategic, and psychological training of the protagonist.

Reviews:
"The great science fiction book for teenagers who don't read science fiction, mainly because it's not about robots but about children against adults."
eldiario.es

"A story with action and ideas that even non-readers will devour eagerly."
iPulp Fiction