In the age of mandatory secondary schooling, truancy and dropping out have become, after “school failure” and “violence,” subject to public debate and have prompted images of uncontrollable if not deviant youths. Numerous research works by French and other scholars have shed light on the discussion about the causes of and correlations with irregular school attendance or dropping out. These point to the operation of the school system, in particular in the French case. Establishing a typology of dropouts is a difficult task, as the processes involved are multi-factorial and depend on the interactions between the school agents, the students themselves, and their close milieu (family, peers). Regarding the elements involved in these processes, the scientific discussion includes the methods used by the researchers.