According to an increasingly popular personality system called the Enneagram, there are nine basic types of people in the world. Each Type sees the world through a different lens, and has different goals, fears, challenges, priorities, and motivations. Once you know the Type of each member of a couple, you have a very good idea of what are likely to be the strengths and challenges of that pairing, and what issues are most likely to come up again and again for them. This book describes each of the 9 Types and how they are expressed within a relationship. This is followed by a separate chapter for each of the 45 possible pairings of these 9 personality types. They help the couple understand where they might get stuck and how they can better work out their differences. The books is based on reports by actual couples of each combination of types, and each chapter has quotations from the couple describing what a relationship of that combination of types is like. Each chapter ends with a few questions for the couple of that particular combination to discuss. This book can be considered a reference book. Although it is very long (555 pages), the average reader can be expected to read through the description of the 9 types, figure out their type and that of their mate, and then turn to the chapter that describes their specific combination. You don't have to know anything about the Enneagram system before starting the book The descriptions are very accessible, and will be useful for all readers.