Gottman is a pre-eminent and world-reknown researcher on marriage. I have yet to read a book that covers all of the topics necessary to have a thriving marriage but this book addresses a number of neccesities. It has a variety of assessments and exercises couples can use to improve their marriage. As a professional counselor working frequently with couples I use principles, assessments, and exercises from this book often. It's not exhaustive, but what it does address it addresses well.