Old Man's War
by John Scalzi

Every good sci-fi novel is based around an idea; in Old Man's War, the idea is that aging citizens of Earth sign up for for military service rather than growing old. They are given rejuvenated bodies and sent to defend the human colonies from the most violent and vicious alien species in the universe. Most of them will die before their time is up, but they just might live long enough to get their own homestead in the colonies and start their lives again. In the book, hundreds of thousands of the elderly choose this option every year rather than face a slow death. But they don't have a clue of what awaits them.

Old Man's War is a clear knock-off of Robert Heinlein's classic sci-fi novel Starship Troopers. To that extent the novel is weak, but it gains its own strength in its discussion of aging, life, death, and what it is to be human. Scalzi has written a second novel, The Ghost Brigades, that also takes place in his created universe, and he plans at least a third novel to fill out the series. I suspect that Old Man's War will be stronger when taken together as part of the saga, but it is still a decent read on its own.