I love this book. It's great. I'm also happy there is not a single romance in the story Thank-you Orson Scott Card! (though there was some random nudity..) Seriously though, read this book. It makes you think, has lots of intertextuality and like Animal Farm was an allegory for a real event, I think comparisons could be made with Ender's Game as well. Oh, and did I mention the awesome battles in zero gravity?
It won the Nebula Award for best novel in 1985, and the Hugo Award for best novel in 1986 - which are the two most prestigious sci-fi awards.It also won the Margaret A. Edwards Award in 2008 which honours an author for lifetime contribution to young adult literature. The U.S Marine Corps even have the book as recommended reading for their officers!
There is a video game, comics, a subsequent series and a shadow series. A movie is also in the works and the screenplay is actually written by the author. They are still casting, but I found a great fan-made trailer:
Clare has already read and reviewed this, so check out her summary.