A while back Amazon had the entire six books in the Old Man's War series by John Scalzi on sale. I'd had the first one on my wishlist so I decided to just buy all the books and hope for the best.
The first book turned out to be really good. Like a new take on The Forever War and Starship Troopers, it's a space war from the POV of a grunt. The new part is that John Perry is originally a 75-year-old guy from Ohio. Like a bunch of old people he joins the Colonial Defense Force for the promise of being young again. The catch is before you can get a new body, you have to do a hitch with the CDF armed forces. The combat body they give everyone is colored green with cat eye's to make it more adaptable to the many alien planets they visit. Unlike many of his mates, Perry survives his encounters with alien races. During a mission gone wrong he meets a Special Forces lieutenant who looks remarkably like his dead wife back on Earth. Later he finds out that the Special Forces troops are made with reconstituted DNA, so the lieutenant looks like Perry's wife because she's sort of a clone of her, only grown in a lab with a lot of combat training embedded. Perry joins the Special Forces troops for a mission, during which he and the lieutenant, Jane Sagan, start to fall in love. After the mission, Perry is eventually retired while Jane remains in the Special Forces.
It was a great book leaning more towards Forever War than Starship Troopers because of the romantic plot. The narration was done in first person that was pretty entertaining.
The problem with the series begins in the second book. It's told in third-person mostly focusing on a guy who's a lab experiment. The CDF grew him as a clone of a traitorous scientist, hoping that some of his memories would remain. Except they don't show up...at first. So the CDF makes him a Special Forces soldier instead and he ends up under the command of Jane Sagan. They eventually find the real scientist, who is trying to create consciousness for an alien race known as the Obin who would make Vulcans seem like a rowdy college frat. The scientist and his clone die and Jane takes his little girl Zoe and retires to a farm with John Perry.
The story is OK but the third person narration is so bland compared to the first book. The clone thing wasn't even that original; Robotech's third series or Mospaeda in Japan did the same thing in the 80s and it was also the plot of the Robotech Invasion video game in the mid-2000s. Maybe Scalzi played that?
The third book gets better as it goes back to focusing on John Perry and goes back to first person narration. Perry, Jane, and now-teenaged Zoe lead a group of colonists to a planet called Roanoke which if you remember history was the first English colony in Virginia--until it disappeared shortly thereafter with everyone seemingly dead. How fitting because there's a new coalition of alien races called The Conclave that wants to destroy Roanoke and any other new colony they don't sanction. At the same time the CDF used Roanoke as bait to lure the Conclave fleet to the planet so they could blow it up to destabilize the Conclave, but since the Conclave survives, they're kind of pissed. To save the colony, Perry cuts a deal with the Conclave. He convinces the Conclave to take a bunch of trade ships to Earth, which is not officially part of the Colonial Union. And through whatever machinations this spares Roanoke, though the Perry family can no longer live there. Or anywhere. What happens to them? Who the fuck knows?
Because the fourth book, Zoe's Tale, is largely a retelling of the third book only as you'd expect from the perspective of Perry's adopted daughter Zoe. Zoe is a big deal with the Obin because of her father creating a sort of consciousness for them. To that end she gets two bodyguards she names Hickory and Dickory because Obin themselves didn't have the consciousness to name themselves. Much of the story then is the same although there are parts that we didn't see much of from Perry's POV that we can see from Zoe's. Like when she travels to the Conclave and saves its leader from an assassination. Unfortunately the book ends with her leaving Roanoke so we still have no fucking idea what happens to the Perry family. For the most part I liked the book even if it was kind of a cheap stunt.
And the fifth "book" isn't much help to answer what happened to John Perry and company. Instead this isn't even a novel. It's actually a bunch of serials published in a magazine that were then strung together and called a new novel. Most of it revolves around a diplomatic team for the Colonial Union as they try to clean up the mess created by John Perry at the end of the third book. It's not bad but again we're back to third person, which Scalzi kind of sucks at--at least compared to first person--and we don't have any of the main characters from the previous books. The closest is Harry Wilson, who was one of Perry's mates early in the first book. If you actually care about the politics of the Colonial Union and Conclave (and who doesn't!) then it's OK. If you liked the first book for its main characters then there's not much here.
The sixth "book" features three novellas instead of a bunch of serials. Each one is written in first person, which is somewhat of a relief. The first one is from the POV of a pilot whose brain was put into a computer so he could pilot a starship on his own. Some bad dudes called Equilibrium are behind this so they can use the pilot to help destabilize the Conclave and Colonial Union. But the pilot double-crosses them and pilots his ship back to the Colonial Union along with some valuable prisoners. The second novella is from the POV of a top adviser to the head of the Conclave. Her mentor blows himself up so he can be a martyr and then she takes over. Finally the last novella is from the POV of Harry Wilson as the Colonial Union and Conclave have to work together to destroy Equilibrium before they can nuke Earth to radioactive dust. Again it's OK if you really give a shit about the politics of all this. For what is (for now at least) the end of the series it's pretty lame that we never get back to the Perry family. It'd be like if Return of the Jedi had just completely ignored Luke Skywalker, Han Solo, Princess Leia, Chewie, and the droids and focused entirely on Mon Mothma and the top brass of the Rebellion. (Or it'd be like the Star Wars prequels that few people besides Tony Laplume liked.)
The problem with the series is that Scalzi didn't really think this through ahead of time. By retiring Perry at the end of the first book, he didn't really have much he could do with him for a sequel. Thus trying to move on to other characters. Then he has to go back to Perry for a third book but since Perry is no longer a soldier, there's not much you can do with him. The colony thing was good, but then making Perry essentially a traitor to his own people again leaves him and his family at a loose end--one that is never resolved. While the fourth book fills in some holes it doesn't move the characters or the series forward a whole lot, especially since we never see Zoe, her parents, or the Obin again.
What we're left with then is a lot of filler material in the form of the last two "books." Like I said, if you care about the political situation then they're fine. But people generally don't read fiction for its political situations. People generally read fiction for characters, for people to root for or despise or whatever. What these serials and novellas do is mostly rob us of character arcs because we get bits and pieces of this character or that character.
Sure you can still sell books this way but they aren't necessarily very good books. If you're going to make a series, you generally want to avoid putting your character in a corner from which he or she has nowhere to go.