For a long time, migration has been neglected both in population and family history. This article briefly explains this absence and shows how, for the past 20–25 years, the concepts of migration and family systems have been elaborated and partly linked. At present, most researchers probably agree that highly diverse configurations existed, such diversity being a consequence of the many factors acting and interacting to determine migration as a part of family and population dynamics. The concept of system, often used but rarely defined, and the notions of ecotypes and sociotypes are discussed in an attempt to go beyond confusion and particularity, to manage complexity, and to articulate macro- and microlevels. Several illustrations of systems observed in preindustrial Europe are also provided. Since the concept of system explicitly stresses continuity and long-term reproduction, the way rural societies have been able to cope with change in industrializing Europe through various compromises between resistance and adaptation is also examined.