Old Man's War is a military science fiction novel written by John Scalzi. It is set in a future where humanity has colonized other planets and is engaged in a war against various alien species. The story follows John Perry, a 75-year-old man who enlists in the military to have his consciousness transferred into a younger, genetically enhanced body. As John joins the fight against the aliens, he discovers the true nature of the war and the secrets behind the military's recruitment process. Old Man's War combines action-packed battles with thought-provoking themes about identity and the ethics of war.
