Old Man's War is a 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 and undergoes a process that rejuvenates his body. He joins the Colonial Defense Forces and is sent to fight against the alien enemies of humanity. Old Man's War explores themes of mortality, identity, and the ethics of war.
