So hard to put down. The author was influenced by Ender's Game and Lord of the Flies, and you can tell. I found the ending too abrupt; as soon as the control of the story left Thomas, the story sagged and lost its sparkle. But the many layers of mystery and grit were well-done. I don't think I've read a scene as creepy and scary as (view spoiler)[Ben in the graveyard (hide spoiler)] in a long time. 
 Booktalk note - p. 38 description of Griever