This sociological work concerns the long-term life chances of children brought up in a variety of circumstances in Uppsala, Sweden, during the first half of the 20th century. It examines the consequences of children's early family environment for their later educational careers, and ultimately, for their mortality risks at different stages of the life-course. Two aspects of family structure are focused upon: the birth order of the subject and the mother's marital status at the time of childbirth. The four studies included in this book are based on the Uppsala Birth Cohort Study, which is a lifelong follow-up of all 14,192 babies born alive at Uppsala Academic Hospital during the period 1915-29. Nearly all these children (97.3%) have been successfully followed up in parish archives and later through computerized linking to census and death registries. While social class is probably one of the most commonly used indicators of childhood social conditions, the two measures of family structure used here may be assumed to capture additional aspects of childhood social circumstances in ways that differ from that of the social structure positions of the parent(s).