The Study collected data for the years 1959-1966 on the cities in which Collaborative Project Centers are located and on these Centers themselves. The data are, on an annual basis, for livebirths, stillbriths, deaths under 24 hrs., 1-7 days, 8-28 days, and 1-12 months by birth weight, gestation length, race, sex, and plurality. Analysis of these two sets would reveal comparative trends in force of mortality', year by year and for the 8 years combined, within each Center, each City, each City-Center combined. Interpretations of similarities and of discrepancies will be attempted based on sample size, sample bias, completeness of reporting, variations in medical practice by City of Center, and indigenous population differences based on varying demographic composition by birth weight, gestion length, race, sex, parity, and plurality. A manuscript is in preparation.