The Five Love Languages of Children
This is a book recommended by a friend. I haven't even finished it and I am recommending it! The theory is that every human understands love in 5 different form, or languages: Quality Time, Words of Affirmation, Gifts, Acts of Service, and Physical Touch. The book explains the 5 "languages," how to determine your child's language, as well as how it can be a part of discipline, how your child learns, and even how they deal with anger. The book ends with an assessment in the form of a game to help you determine your child's primary language.
Also, there is a sister book called The Five Love Languages: How to Express Heartfelt Commitment to Your Mate.