A world-renowned relationship expert shares his research about love and what it takes to develop a trustful, intimate, and emotionally fulfilling bond.

In this insightful book, celebrated research psychologist and couples counselor John Gottman plumbs the mysteries of love and shares the results of his famous "Love Lab": Where does love come from? Why does some love last, and why does some fade? And how can we keep it alive? Based on laboratory findings, this book shows readers how to identify signs, behaviors, and attitudes that indicate a fraying relationship and provides strategies for repairing what may seem lost or broken.

What Makes Love Last? Introduction
Angel: I have something to say-

George: Hold on. I'm not finished.

Angel: What I am trying to say-

George: See and this is what I'm talking about-

Angel: Right, I know, because I do not-

George: You cut in-

Angel: I have to say something now-

George: No. Because when you cut in-

Angel: I have something to say here.

George: SHUT UP!

Angel and George were newlyweds juggling long work hours while raising two toddlers. That's a situation tough enough to put pressure on any marriage, but you wouldn't need a background in research psychology to recognize that this one was in trouble. The dialogue above is a snippet of the argument they had in my research lab. They sparred without end over who worked harder, who did more housework and who said what when. Angel and George, like many embattled couples, gave up on their marriage and divorced. This outcome was not unexpected considering how damaged their relationship was. When I met with them, they could barely look at each other without scowling and rolling their eyes.

For years I have invited couples like Angel and George to take part in experiments at my "Love Lab," the media's nickname for the facility at the University of Washington in Seattle, where I subject long-term romance to scientific scrutiny. In a typical study I analyze couples while they converse about everyday topics as well as when they argue. I interview them together and individually. I've even observed couples while they spend an entire day at the Love Lab's studio apartment, which comes complete with sofa, loveseat, TV, kitchen, a lake view, and video cameras hooked to the walls, which record every moment of their interactions. (The bathroom, of course, is off limits.) Thanks to these studies, I have accumulated nearly four decades' worth of data-a library of how and what partners say to and about each other, and their physiological reactions. These days I also conduct similar exercises with couples who are not part of any study but wish to receive a scientific assessment of their relationship's staying power.

When couples like Angel and George enter the Love Lab, we hook them up to enough sensors and wires to elicit quips about Dr. Frankenstein. While they adjust to the equipment and their surroundings, information begins to stream from the sensors, indicating their blood velocities, heart and pulse rates, the amount their palms sweat, and even how much they squirm in their chairs. A video camera records all of their words and body movements. On the other side of a one-way mirror, my assistants, surrounded by equipment readouts, and the requisite collection of empty cola cans, scrutinize the subtle interplay between the couple's biological reactions, body language, facial expressions, and words.

The most frequent experiment I conduct is called the conflict discussion, in which we ask the couple to converse about an area of disagreement for fifteen minutes. To facilitate the analysis of their facial expressions during their disputes, I train a separate video camera on each of them so I can view their faces in real time on a split screen.

It no longer surprises me when our couples are able to relax and "let it rip" despite the staring cameras. Still, I find that most people do curb their behavior in the lab compared to when they squabble at home. But even when partners are acting "camera ready," they can't hide from the accuracy of my sensors.

Close analysis of so many couples over the years led me to formulate seven key principles that can improve the odds of maintaining a positive relationship. Described in The Seven Principles for Making Marriage Work, they e