A renewed interest in the study of human mobility, migratory movements, exiles and other forced migrations, has lately turned to the use of the migrants' private sources. Therefore a new set of theoretical and methodological approaches has arisen, linked with the question of how to make proper use of documentary sources for a better understanding of these historical phenomena. These questions are the point of departure of this book, that collects a series of research papers, chronologically located between the 18th and 20th centuries, of well-known specialists that present their reflections on the close links between migration and personal documents.