As mankind advances into space with the help of the new collapsar jump, they discover an intelligent race, the Tauren. When some ships full of settlers are destroyed by the Tauren, humanity declares war on them. William Mandella is one of the first to fall under the new Elite Conscription Act, and instead of following a career in physics, he is trained as a soldier and enlisted to fight the Tauren. But thanks to the effects of relativity (time dilation to be more specific), for every day and month he has spent on flight between the battle zones, on Earth years have gone by. Estranged from his own culture, chained to a past that doesn’t exists anymore, he enlists again and fights in a war that seems to go on forever.
Many good things can be said about the book, the description of the fights, the soldiers, the fears they have, how they behave, all that rings very true. I also liked the physics (apart from the collapsar jumps) and how they affected the whole war. The effect that the troops before a fight never knew if they would battle against an alien group that is locked in their past or has already advanced weapons from their future thanks to time dilation is incredibly clever.
But there were also some things I disliked, the development of Earth’s society felt very implausible, and the conclusion of the Forever War (not the book, but the war itself) was strange and didn’t work for me.