Old Man's War
John Scalzi
 The novel tells the story of John Perry, a 75-year old retired advertisement writer, who joins the Colonial Defense Forces who protect human interplanetary colonists. Applicants are required to sign a letter of intent when they are 65—which John and his now deceased wife Kathy had signed 10 years prior to the beginning of the story. After visiting his wife's grave to say good bye (as volunteers can never return to Earth) Perry takes a space elevator to the CDF's Henry Hudson, where he meets a group of fellow retiree volunteers who dub themselves the 'Old Farts'. Following a series of bizzare psychological tests, Perry's mind is ultimately transferred to a new body with enhanced musculature, green skin, and yellow (almost cat-like) eyes. This new body, based on his original DNA, has been modified for enormous strength and dexterity, and supplemented with several proprietary products including artificial blood, enhanced eyesight and other senses and most critically, a BrainPal—a neural interface that allows Perry to communicate with other members of the CDF through thought. After a week of frivolity and orgies, Perry lands on Beta Pyxis III for basic training, during which the CDF's heritage in the United States armed forces is made clear when the recruits are taught the Rifleman's Creed. After Perry learns that his Master Sergeant adopted one his advertisements from Earth as a mantra, Perry is given the dubious job of platoon leader during the weeks of training before he is shipped out to the CDF's Modesto. His first engagement is with the Consu, a fierce and incredibly intelligent, though religiously zealous, alien species. Perry improvises a tactic which enables the CDF to win this first battle quickly. This is soon followed by a number of battles with, among others, the Whaidians and the tiny Covandu. By the end of this last engagement Perry begins to suffer psychological distress over killing the Liliputian Covandu and accepts that he has transformed both physically and mentally. Now a war-seasoned veteran, Perry then participates in the Battle for Coral. The CDF plans to rapidly transport in a small number of vessels to Coral, which was assaulted and conquered by the predatory Rraey. Somehow, the Rraey are able to predict the trajectory of the vessel's skip drives (a feat that should not be possible) and use this knowledge to destroy the fleet. Perry's quick thinking allows him and a small number of others to escape in a shuttle craft and make for the planet's surface, where they are shot down and crash violently. Perry is left for dead, only to be rescued by the mysterious "Ghost Brigades", the Special Forces units of the CDF. Perry is struck by the sight of the leader of the Ghost Brigades rescue team, Jane Sagan, an apparent clone of his dead wife Kathy. After being repaired, Perry tracks down Jane Sagan, who turns out to have been grown using Kathy Perry's DNA, as legally allowed by her letter of intent to join the CDF. Unlike John, Jane has no memories of her previous life, but upon learning of Kathy, Jane seeks to learn more from John about being a regular born ('realborn') person and what kind of life one can have outside the CDF. Jane manipulates her chain of command to promote John to an advisory role (as a full lieutenant) to gather information from the Consu during a ritualistic meeting to share information. Perry discovers that the Rraey have received tachyon technology from the Consu, allowing them to predict the location of their ships. Perry also manipulates command to get the last two of his friends from the 'Old Farts' transferred to Military Research. Jane and John then participate in a Special Forces operation in an attempt to capture or destroy the borrowed Consu technology in advance of a major invasion on Coral. While John is instrumental in the successful outcome of the battle, in particular, saving the data relating to the machines, which are destroyed, he loses track of Jane as she returns to the insular Ghost Brigades. At the conclusion of the book, Perry has been promoted to captain following his deeds at Coral and despite the separation, holds hope of reuniting with Jane when their terms of service conclude.