The Ghost Brigades, by John Scalzi, is the follow-up novel to Old Man's War. It's not a direct sequel, though subsequent events will show that it actually is, in a sense. Instead, it features the love of John Perry's life, Jane Sagan, Special Forces ("Ghost Brigades") officer. This book is a lot grittier than the Old Man's War, and the point of view choices are much different. It's just as effective, though, with fewer of the faults of the previous book.
In the future, humans have gone to the stars, but they aren't allowed to go back. Humans have colonized planets, but they have run up against a number of alien races that don't want them there, and war inevitably develops. Jane Sagan, a lieutenant in the Ghost Brigades (the Colonial Defense Forces "Special Forces"), captures an alien scientist with information about a triple alliance of races who don't seem very likely to ally. They also discover that the instigator of this plot to start a war with the CDF is a human traitor, a genius named Charles Boutin. Before he left, he downloaded his consciousness into a computer, so the CDF decide to clone his body and try to install his consciousness into it, to see if they can figure out Boutin's plan and motivations. It doesn't seem to work, so they give the resulting "person", Jared Dirac, to the Ghost Brigades for their training and use. But as time goes on, the other consciousness begins to emerge, and Jane will ultimately have to determine whether Jared is with them, or that he must be killed.
The Ghost Brigades is an awesome continuation of Scalzi's series, taken in a whole new direction so that it doesn't go stale. He doesn't continue the adventures of John Perry, as that could get boring. He's just a soldier in a never-ending war, and Scalzi would have to come up with something really creative to make that interesting. Instead, he shows us the Ghost Brigades, something that he gave us a part of in the previous book, only hinting at the potential.
Also, this book has much more of a point than before. While Sagan plays a vital role in the book, it's not really about her, and thus it's not just "tales of the Special Forces." Everything is geared to Boutin and his ultimate plan, and the story centers on Jared because of this. We see his integration into the Ghost Brigades, we see his training. But it's not the seemingly aimless training that Perry went through, a means to an end to illustrate the galaxy Scalzi has created while introducing us to the concepts. It shapes Jared, highlighting just how integrated all Ghost units are (by using their brain-implanted computers, called Brainpals).
While the story is much more focused, the points of view aren't. We get Sagan's and Jared's, but we also see some of the officers (both Ghosts and regular CDF), illustrating what life is like in the officer's corps. It also gives us a big-picture view of what is really going on, and the stakes that are at risk if Boutin's plan comes to fruition. This provides Ghost Brigades a broad scope even as the story itself narrows in on one problem. We see some of the truth behind the CDF, both Boutin's warped view of it (which sounds somewhat convincing if he wasn't such a maniac) and the reality of it.
I would be remiss if I didn't mention Scalzi's brilliant characterization. These people jump off the page, from the more minor characters to Sagan and Jared. I loved General Szilard, head of the Ghost Brigades. The Ghosts aren't supposed to have a sense of humour, but he has obviously been around long enough to develop one. His interactions with the CDF liaison, Colonel Robbins, were wonderful, especially in the Officers' Mess, where underlings can attend but can't eat. The scene with Szilard and the cookie are worth the price of admission alone.
However, it's Sagan and Jared that make this book sing. Sagan is reluctant to be Jared's guardian, but she takes on the task and develops a respect for him even as she's not sure she can trust him. She's an intelligent leader, compassionate, and thorough. My first thoughts on Jared when I began this review was to criticize the emotional distance we seem to have with him at times. He develops a love for one of his squadmates, but it never actually seems "real." However, on thinking about it, that just illustrates Jared's emotional isolation even more. He is a man (boy, really, as he's only a year or so old at the end of the book) who was grown for a purpose. He has even less control of his life than do most of the Ghosts, who while bred only for combat, at least know what the meaning of their life is. Jared doesn't even have that certainty. He'll always have that disadvantage, and Scalzi brings that out perfectly.
Finally, the action is relentless, but again it's not your typical military SF. Scalzi doesn't dwell on the technology or the broad military tactics. There are some pretty horrific deaths in the book, but nothing too disgusting (except in concept, of course, such as falling from low orbit). He just gives the reader enough to understand what's going on and then gets to the action itself. This time, he puts a little philosophy in there as well. He did that with Old Man's War too, but it doesn't feel as forced this time around.
The Ghost Brigades seems to wrap up the personal storyline of the series' main protagonists, but it sets up some huge events for the galaxy at large for the next book. There are certainly no major flaws to hinder the enjoyment of this wonderful book. Unless you have a huge aversion to any kind of military SF, pick this one up.