"This paper examines differentials in observed and forecasted sex-specific life expectancies and longevity in the United States from 1900 to 2065.  Mortality models are developed and used to generate long-run forecasts, with confidence intervals that extend recent work by Lee and Carter (1992). These results are compared for forecast accuracy with univariate naive forecasts of life expectancies and those prepared by the Actuary of the Social Security Administration."