Sweden--where 86 percent of mothers of preschool children are in the labor force--is an ideal place to examine new models for the successful combining of working and parenting. In that country, a concerted effort--by government, organized labor, and other institutions--has been made to equalize the burdens of parenting between men and women, and to adapt employment conditions to meet parental needs. Moen examines how the changing patterns of work-family relations have affected Swedish parents of young children. Drawing on national survey data collected from 1968 to 1981, she describes the changing work attachments of mothers of preschoolers, traces the of implications these changes for the well-being of both mothers and fathers, and offers evidence about the consequences of public policies adopted to facilitate the reconciliation of work and family roles.     Moen's analysis shows that women, assuming an unequal burden, were far more prone than men to psychological strain and daily fatigue. However, the gender differences narrowed over the 1978-1981 period: Mothers  experienced a reduction in psychological distress, while fathers reported an increase in daily fatigue. Part-time work and parental leave policies enhanced the well-being of mothers, while worktime discretion improved the well-being of both parents.     The lessons for the United States are critical, since the major factors capable of improving the well-being of Swedish parents--liberal parental leaves and reduced working hours--are not available to most American working parents. In fact, there are now more American than Swedish mothers of preschoolers working full-time hours. The Swedish experience provides a valuable point of reference as well as concrete examples of ways that Americans might deal with critical issues of work and family life.