If children live with hostility they learn to fight. If children live with kindness and consideration, they learn respect. Excerpt from "Child Learn What They Live" by Dorothy Law Nolte.
I found this book to offer pragmatic and practical approaches to understanding and dealing with defiant children. Dr. Jeffrey Bernstein is a licensed psychologist who specalised in child and family therapy. Much of the ideas in this book are backed by research and his case history.
Lisa and I read this at roughly the same time. This proved a useful strategy because we could discuss the content in relation to our day-to-day parenting.