The Whole Brain Child by Daniel J. Siegel (neuropsychiatrist and author of the bestselling Mindsight) and Tina Payne Bryson
No Drama Discipline by Daniel J. Siegel and Tina Payne Bryson
I can't recommend these books enough. For those who have been practicing gentle discipline, so much of what they write about will be familiar. There is so much brain science to explain why children act the way they do and to support gentle discipline. I love how the goal in the first book is integration between left and right brain. In the discipline book, the authors start out by stating discipline means "to instruct". So much great information in these two books!
I found both at my library, and then ordered them to participate in a book study at my son's school.