AS WE REFLECT upon the changes of residence of friends and acquaintances we recall many persons whose migration from one town to another or from one county or state to another was motivated by circumstances which were peculiar to them as individuals or as a family group. An appreciable amount of labor-turnover, some of which results in migration to another town, is due to personal factors. A mechanic from Camden, N. J., may secure a job in Philadelphia, Pa., through his brotherin-law, while a pharmacist from Philadelphia moves to Camden in order to work in his uncle's drug-store. Many thousands of girls leave their farm or town homes when they marry; husbands die and widowed mothers go to live with their married daughters; girls have children illegitimately and their families move away; husbands desert wives; criminals attempt to escape justice; thousands of persons just drift about, their migrations unrelated to economic or social conditions surrounding them. The inevitable diversity of these individualistically motivated movements of people challenge the attempts of investigators of internal migration to find a common denominator which will characterize the persons as a group. The assumptions underlying studies of migration are in terms of socioeconomic forces which are pushing people out of the source or drawing them to the goal. If these individuals, motivated by unique personal situations which may have little relation to the socio-economic forces, constitute an appreciable percentage of those who leave the migration source, their inclusion in the migrant group obscures differentials which may exist between migrants and non-migrants. Realization of the fact that 25 million people in this country live in states other than those in which they were born, and that in addition many millions have moved about within their native state, tempts one to conclude that mobility is almost the rule rather than the exception in our culture. With mobility such a common phenomenon, it would be indeed remarkable if all, or even a majority of migrants in any given situation, were motivated by factors which are reducible to any common denominator.