According to most relationship books, the key to a solid marriage is communication, communication, communication. Phooey, says John Gottman, Ph.D., author of the much-lauded Why Marriages Succeed or Fail. There's much more to a solid, "emotionally intelligent" marriage than sharing every feeling and thought, he points out--though most couples therapists ineffectively (and expensively) harp on these concepts. Gottman, the director of the Gottman Institute, has found through studying hundreds of couples in his "love lab" that it only takes five minutes for him to predict--with 91 percent accuracy--which couples will eventually divorce. He shares the four not-so-obvious signs of a troubled relationship that he looks for, using sometimes amusing passages from his sessions with married couples. (One standout is Rory, the pediatrician who didn't know the name of the family dog because he spent so much time at work.) Gottman debunks many myths about divorce (primary among them that affairs are at the root of most splits). He also reveals surprising facts about couples who stay together. They do engage in screaming matches. And they certainly don't resolve every problem. "Take Allan and Betty," he writes. "When Allan gets annoyed at Betty, he turns on ESPN. When Betty is upset with him, she heads for the mall. Then they regroup and go on as if nothing's happened. Never in forty-five years of marriage have they sat down to have a 'dialogue' about their relation