This bulletin examines the baby boom, its causes, its size, and its impact on U.S. society. Nearly 42 million births occurred in the U.S. from 1955 to 1964. Several reasons are given for this baby boom which interrupted a century long fertility decline. Demographically the primary causes were more people marrying and having at least two children at earlier ages. Economic conditions were favorable. The demand for labor was high and the young people entering the job market were few. Sociological causes of the baby boom were the pervasive pro-marriage, pro-housewife, pro-natalist forces prevalent at that time. To accomodate the baby boom generation, school and college facilities expanded enormously in the 1960's and early 1970's. Unemployment and crime rates rose and subsided with the passage of this generation through late teenage and early adulthood. In the 1980's with the bulk of the baby boom generation aged 20-30, housing demand will remain high and annual birth numbers will increase even if the rate of childbearing hovers below replacement level at about 1.8 births per woman as it has since 1974. Per capita earnings and overall labor productivity should improve as the baby boom group settles into experienced middle age in the 1990's. Society's greatest challenge will come as this generation reaches retirement age. The 65 and over population will nearly double from 31 million in 2000 to almost 60 million in 2030. The ratio of active workers paying into the Social Security pool to elderly beneficiaries will fall drastically. (Author/RM)