The Forever War is a 1974 landmark military science fiction novel written by Joe Haldeman that uses an interstellar conflict to deliver a powerful allegory about the senselessness of war and the isolation felt by returning veterans.

Drawing heavily from Haldeman’s personal experiences as a drafted combat engineer who was wounded in the Vietnam War, the book is widely considered a foundational classic of modern science fiction.

Plot

The narrative follows William Mandella, a physics student drafted into an elite United Nations military unit tasked with fighting the Taurans, a newly discovered, enigmatic alien species. The core mechanic driving the book’s psychological tragedy is time dilation.

• The Physics of Travel: To engage the enemy, human soldiers must travel through collapsars at near-light speeds.
• The Cost of Dilation: While a mission lasts only a few months or years for Mandella, decades or centuries flash by on Earth.
• Alienation: Every time Mandella returns from battle, Earth’s society has evolved dramatically, rendering it unrecognizable. Language, currency, global economics, and even basic human sexuality shift entirely, making the soldiers biological and social relics out of time. 

It’s an anti-war story told from the soldier’s point of view.