Dr. jae-sok Choi carried out researches mainly on Korean Social history such as Korean family and kinship systems, the main features of which are the peculiar characteristics of Korean family and the mid-seventeenth-century changes in Korean family systems. Among his theses on Korean family the most interesting and important are those dealing with the changes in the structure of Korean family and kinsfolk. What was most influential was marriage residence rule. Thirteen theses comprise this book, twelve of which concern Korean family.