The ideal family includes two married people and their biological children. The nuclear family should be the primary source of emotionally intimate relationships. And the difficult challenges that face families today threaten to destroy the basic unit of American society. So says conventional wisdom.

Thankfully, Al and Tipper Gore lay all those truisms to rest in their thought-provoking book, Joined at the Heart: The Transformation of the American Family. The work is devoted to describing families as they really are, identifying the challenges those families face, and suggesting that if there ever was a golden era of the family, this is as likely a time as any.

The Gores earned the right to opine on families by organizing the annual Family Re-Union conferences forums for research about family issues for the last 11 years. In the book, they use anecdotes from interviews with several families to illustrate and support research data and theoretical work from a large group of sociologists, psychologists, economists, and other social scientists. From the outset, it is clear that they recognize their own version of "family"-they've been married forever and have four children together-is not the norm. Their interview subjects include the Fadleys (the product of two divorces and children from three sets of parents, including one child born out of wedlock); the soon-to-be Logans (two white gay men who adopted an African-American child and a Latino/African-American child and are taking on a new name-Logan-to underscore their family connection); and the two-home family of severely disabled Brett Philpott, who divides his days between three primary caregivers-his thrice-divorced dad; his mother, and her husband, who considers Brett's biological father to be his best friend.

They and the other families are presented as an honest ideal of what it means to be family in America today. As the Gores say, "family is quite simply the people about whom you care the most in the world, regardless of their legal or biological relationship to you."

If this definition surprises, it is because it is fairly new, and those who cast a nostalgic eye for the better families of earlier times still haven't figured it out. When, after thousands of years, the nuclear family transcended the extended family in importance, it emerged to serve as an economic unit-a group of people who worked together simply to survive from one generation to the next. It is only in the last few generations that the family has come to be seen as the locus of emotional intimacy and love, which puts rising expectations-and indeed pressure-on the quality of family relationships. This, in turn, has prompted a re-ordering of the process. Today, "emotional connection" means "family" instead of the other way around.