4. Ender's Shadow by Orson Scott Card
I spent the past couple days visiting Granada and my friend kindly offered this to me to read on the bus! I read Ender's Game and Speaker for the Dead a couple years ago, and while I'd heard great things about the Bean split-series, I never got around to reading it.
It was so satisfying! I wouldn't go so far as to say it's better than Ender's Game, but it's definitely on the same level. I never imagined that Bean's upbringing was so different from Ender's, or really anything that I learned about Bean from this novel. In this book, we get to see the imagined Europe of Card's futuristic world. It is immeasurably bleak and brutal, but the scary part is how realistic it feels. This nightmare is where I think Card does what he does best; evoke all the evil impulses of humanity and represent them in a childish society. No matter that these kids are impossibly young, survival is survival. Survive or die, in the world of Bean's childhood.
When Bean does get to Battle School, his point of view and decisions are very different from Ender's, though no less brilliant. In fact, we learn that Bean actually is smarter than Ender, he's just less physically fit and a less charismatic leader. Knowing this changes the way you understand Ender and the interactions between Ender and Bean
There's plenty of set up here for later books, and the latter half of the book dealt with some plot a little too quickly, but you're reading for the characters and complex depravity of Card's imagination. Shadow of the Hegemon is next, don't know when I'll get to it, but I intend to.