Twenty years ago, Stephanie Coontz asked of traditional marriage, “What tradition?” Now she returns to examine its contemporary state—what threatens its prevalence and what freedoms it can create for all people.

Ninety percent of the world’s people live in countries where marriage rates have plummeted since the 1980s, with the Western world experiencing especially steep drops. Almost everywhere, marriage has declined most among men and women with the lowest levels of education or earnings. And highly-educated and high-earning women are actually more likely to marry and less likely to divorce than in the past. But such women often express more ambivalence about getting married than other women—and typically postpone doing so until later in life.

Still, rather than devaluing marriage, people all around the world overwhelmingly describe it as the highest expression of commitment they can imagine. And most people say they eventually want to marry even while they increasingly express uncertainty about whether they will end up doing so.

In her new book, For Better and Worse, Stephanie Coontz unravels the origins of these paradoxical trends. Using the past to illuminate the present, she shows how shifting marital ideologies, gender relations, sexual mores, and emotional mind-sets over time have bequeathed us a welter of contradictory expectations and habits that often sabotage our attempts to build mutually satisfactory relationships. “Traditional” roles and values that once promoted successful marriages are now a recipe for relationship failure. Only by undoing the legacy of marriage’s “problematic past,” Coontz argues, can we help individuals and society at large navigate the “challenging future” of marriage.