Understanding personality type can help couples celebrate their differences. For long-term couples, it can help make their relationships more satisfying. For couples who are in the early stages of a relationship, it can help them get to know each other better. And for single people, type is a tool that can help them understand why past relationships fizzled out instead of blossoming into long-term partnerships.

Says Barron-Tieger, "We all want to be with someone who loves us for who we are. Who doesn't want that?"