Up to now, the extensive sociological literature on mobility has been based around the survey method. As a result, we have access to abundant statistical data, but there is little information available to explain how and why people follow particular life paths. To overcome these limitations, the authors have developed an alternative, complementary approach using life stories, case histories of whole families over several generations, or case studies of local communities. Employing the case-study approach does not prevent the identification of structural trends; on the contrary, it allows us to analyse those collective processes through their local effects, restoring the links with the classics of sociological thought.