A psychotherapist who is a renowned expert on divorce, Wallerstein now looks at happy marriages and what makes them work. This is a study of 50 Bay Area couples, who married in the 1950s, 1960s, 1970s, and 1980s. The criteria for the couples were that both husband and wife had to consider the marriage a happy one, have at least one child, and to have been married a minimum of nine years;both first and second marriages. (BOOK)