Well, this is part of the field of Science Fiction literature devoted to futuristic warfare, which is exemplified by Heinlein's Starship Troopers and Haldeman's Forever War. But Scalzi puts his own twist on this genre in an initial novel that sets him up for more sequels in a very interesting universe.

I was hooked right from the opening sentence, and for the first part of the book it was almost like finding some Heinlein I had somehow missed. Scalzi is just that good. But it is not the bildungsroman that Heinlein wrote, just the opposite in fact, since the main character is in his 70s (there is a reason it is called the Old Man's War). For me that makes the viewpoint even more interesting since I closer in age to the main character here than I am to Heinlein's protagonist. But here we have someone at the end of life who gets a "new lease" as it were, and it is a fascinating idea that is somewhat plausible in light of developments ("We have the technology.")

The book gallops right along, and is a great trip. I recommend it