Abstract: Linked birth and infant death certificates allow measurement of birthweight-specific infant mortality. Jack Smith, MS, to whom this issue of the American Journal of Preventive Medicine is dedicated, played a key role in the National Infant Mortality Surveillance (NIMS) project. NIMS provided national data on birthweight-specific infant mortality for the 1980 birth cohort, updated data previously collected by the National Center for Health Statistics (NCHS) for the 1960 birth cohort, and supported NCHS’s implementation of an annual linked file in 1983.