Caleb: Shadowhunter's Codex - because rules are there to be followed that's what erudite teach.
Four: Hunger Games: Mockingjay- Because revolutions are inevitable.
Eric: Cruel Crown- Because people's backstories are key to how they act Eric is a great example of that.
Will: Champion- You just like it and it is the only thing you have from your old faction.
Peter: Red Queen- It reminds you and more him that there will always be people who have more power than you and him.
-Crystal