John and Julie Gottman, world-renowned for bringing an evidence base to couples therapy, report here the results of a second empirical revolution in understanding couples and families. This change is not based on their guesswork, but on state-of-the-art science. The book you hold in your hands finally completes the old general systems theory of the 1960s, which metaphorically described processes but did not actually research them. A new general systems theory and therapy is presented here, one which will have profound implications for powerful clinical work with both couples and families. This new theory is based on 45 years of careful basic scientific research with thousands of couples and families, including synchronized observational, interview, physiological, and questionnaire data. The Gottmans have studied some families for as long as 20 consecutive years. Their work has led to their highly replicated ability to precisely predict the future of relationships, relationship happiness, and whether couples will divorce or not with as much as 94% accuracy. Their empirical work has also led them to develop and test a theory of specifically what makes relationships work. Each construct in this theory is precise and measurable and it is all written about and described here. This book presents an original new way of understanding relationships and families. Both theoretical and highly practical, and it will help clinicians become more effective in their everyday work.