Genealogies and family history, an identity to convey. The popular practice of genealogy has been developed steadily since the 1970s. The phenomenon can be observed in North America as well as in Western Europe. There is a strong trend that comes with the emergence of a new economic activity. The commitment of the practioners seems on the contrary to indicate deeper motivation. The question then arises of identifying the underlying forces. The analysis of research files entrusted to a professional genealogist makes it possible to suggest lines of thought. The nees to release the weight of memory and to build a family narrative conveying an identity transmissible to future generations is part of it.