The Forever War - Joe Haldeman

Private William Mandella is a hero in spite of himself--a reluctant conscript drafted into an elite military unit. He never wanted to go to war, but the leaders on Earth have drawn a line in the interstellar sand--despite the fact that their fierce alien enemy is unknowable, unconquerable, and very far away. \n \nThe monumental Hugo and Nebula award winning SF classic-- Featuring a new introduction by John Scalzi \n \nThe Earth's leaders have drawn a line in the interstellar sand--despite the fact that the fierce alien enemy they would oppose is inscrutable, unconquerable, and very far away. A reluctant conscript drafted into an elite Military unit, Private William Mandella has been propelled through space and time to fight in the distant thousand-year conflict; to perform his duties and do whatever it takes to survive the ordeal and return home. But home may be even more terrifying than battle, because, thanks to the time dilation caused by space travel, Mandella is aging months while the Earth he left behind is aging centuries...\n