The 20th century beheld a dramatic transformation of the family. Some Kuznets style facts regarding structural change in the family are presented. Over the course of the 20th century in the United States fertility declined, educational attainment waxed, housework fell, leisure increased, jobs shifted from blue to white collar, and marriage waned. These trends are also observed in the cross-country data. A model is developed, and then calibrated, to address the trends in the US data. The calibration procedure is closely connected to the underlying economic logic. Three drivers of the great transition are considered: neutral technological progress, skill-biased technological change, and drops in the price of labor-saving household durables.