Old Man's War is a military science fiction novel written by John Scalzi. It is set in a future where senior citizens can enlist in the military to fight in interstellar wars. The story follows John Perry, a 75-year-old man who joins the Colonial Defense Forces and undergoes a rejuvenation process to become a young soldier. Old Man's War explores themes of mortality, identity, and the human cost of war. It is known for its fast-paced action and engaging characters.
