This is the first systematic study of patterns of social mobility in Ireland. It covers a recent period -- the 1960's -- when Ireland was undergoing rapid economic growth and modernization. The author thus was able to test the widely accepted hypothesis that growth weakens class barriers. To his surprise he found that it did not. Social mobility increased somewhat, but among mobile men the better jobs still went to those from advantaged social class origins. Despite economic development and demographic change, the underlying link between social origins and career destinations remained unchanged.