Ever since I found this lying on one of my father's bookshelves, I've loved this book. It is one of those books that few know about, never receiving the adulation it deserved. It has that rare quality certain books have where you'll probably never meet anyone who read it that didn't love it. In fact, I'd be surprised if they had not read it a few times.
Around fourteen I had just finished reading Starship Troopers. My head was spinning with powersuits and giant insect aliens. When I found Armor, I was initially skeptical that an unknown like John Steakley could top the legend Heinlein. I was wrong. Starship Troopers is a good book, but Steakley's Armor is a great book. And possibly my favorite book of Science Fiction.
The book is divided into three parts, the first following Felix and the second Jack Crow. One character is melancholy, while the other bellicose. The stories are told with the speed of a train, flying through the experiences of these two men. Until their stories converge in the third part of the book, where Steakley keeps stoking more and more speed from that train, until it smashes right in to you at the end.
Frankly, it would surprise me if you didn't read it in 3 sittings or less.