Not books, but 11-13 is an age range where boardgames start to become enjoyable, and there is a pretty strong German tradition for games appropriate to that age range (so strong, in fact, that this complexity/duration range is called "Eurogames" in the American jargon). Pandemic is one that's loads of fun. Power Grid and Carcassonne are both quite simple to learn and reasonably, respectively very, challenging to master.

- Jake

Friends come and go. Enemies accumulate.