A SF classic or a superficial military SF?
For me it was more of the latter. Read on its own and not in the context of all the similar books that have proceeded it, this is a fun, military SF novel. The book is well written and entertaining.

The plot sees John Perry, a 75-year-old retired advertising writer, joining the Colonial Defense Forces. They protect human interplanetary colonists. Volunteers sign letters of intent and provide DNA samples at age 65, which John and his now deceased wife Kathy had done ten years before the beginning of the story. After visiting his wife's grave to say goodbye (as volunteers can never return to Earth), Perry takes a space elevator to the CDF ship Henry Hudson, where he meets fellow male and female retiree volunteers who dub themselves the "Old Farts".

Following a series of sometimes bizarre psychological and physical tests, Perry's mind is transferred to a new body based on his genetic material. His new body is a younger version of himself, but genetically engineered with enhanced musculature, green skin, and yellow cat-like eyes. He now possesses enormous strength and dexterity,nanobot-enhanced artificial blood, enhanced eyesight and other senses, and a BrainPal—a neural interface that, among other capabilities, allows Perry to communicate with other members of the CDF via thought.

After a week of frivolity and orgies in their new bodies, Perry and the other recruits land 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 drill instructor adopted one of his advertising slogans as a personalmantra, Perry is given the dubious job of platoon leader during the weeks of training before he is shipped out to the CDF ship Modesto. His first engagement is with the Consu, a fierce and intelligent, though zealous, alien species. Perry improvises a tactic which enables the CDF to win this first battle. This is followed by several battles with, among others, the bear-like 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 veteran, Perry participates in the Battle for Coral. The planet contains coral reefs valuable to the attacking Rraey, as well as a human colony (the Rraey also have a taste for human flesh). The CDF plans to counterattack with a force before the Rraey establish their coral strip mining operations, but the Rraey have somehow obtained technology to predict the appearance of a space ship's skip drive (a feat that should not be possible) and use this knowledge to ambush and destroy CDF ships as they arrive in the Coral system. Perry's quick thinking allows him and his fellow soldiers on a transport shuttle to escape the wreckage of the Modesto and make for the planet's surface, but they are shot down and Perry is the only survivor of the crash. Perry is left for dead by a Rraey search party (who find CDF soldiers inedible), but he is rescued by members of the mysterious "Ghost Brigades", the Special Forces units of the CDF. Perry thinks he has died when he sees a younger green version of his dead wife Kathy, who in reality is Jane Sagan, the leader of the Ghost Brigades rescue team.

After being repaired, Perry tracks down Sagan, who turns out to have been grown based on Kathy Perry's DNA sample, as legally allowed by her letter of intent to join the CDF. Unlike John, Jane has no memories of Kathy's life, as she is only six years old, but after learning about Kathy, Jane seeks to learn more from John about being a "realborn" person and what kind of life one can have outside the CDF.

Sagan manipulates her chain of command to promote John to an advisory role (as a lieutenant) to gather information from the Consu during a ritualistic meeting to get information. Perry discovers that the Rraey had received the skip-drive detection tachyon technology from the Consu, which was used to set up the ambush at Coral. Perry also manipulates his chain of command to have the last two of his friends from the "Old Farts" transferred out of combat duty to military research. Sagan and Perry then take part in a Special Forces operation in an attempt to capture or destroy the borrowed Consu technology in advance of a major attack to recapture Coral from the Rraey. Perry is instrumental in the successful outcome of the battle by capturing the technical manual for the Consu detection system (which was destroyed in the fighting), and saving Sagan's life after she is wounded. He never sees her again after delivering her to a shuttle which returns her to the secretive Ghost Brigades.

At the conclusion of the book, Perry is promoted to captain following his deeds at Coral and despite the separation, holds hope of reuniting with Sagan when their terms of service conclude." transferred out of combat duty to military research. Sagan and Perry then take part in a Special Forces operation in an attempt to capture or destroy the borrowed Consu technology in advance of a major attack to recapture Coral from the Rraey. Perry is instrumental in the successful outcome of the battle by capturing the technical manual for the Consu detection system (which was destroyed in the fighting), and saving Sagan's life after she is wounded. Yet, he never sees her again after delivering her to a shuttle which returns her to the secretive Ghost Brigades.

At the conclusion of the book, Perry is promoted to captain following his deeds at Coral and despite the separation, holds hope of reuniting with Sagan when their terms of service conclude.

What is lacking is some inventive and new SF ideas. The novels that it draws from are in more original, more inventive and better. There is no real attempt to push out new ideas about how technology may impact on us in the future. Other writers have explored skip drives, nano tech cloning, splicing DNA before. If read as an military adventure novel, then its a gripping read. If you're looking for anything deeper then it'll disappoint you.

Buy a copy of the book HERE.