This essay introduces the ERQ special issue on qualitative research in contemporary Italy's prison system. The traditional sociological categories regarding imprisonment, related to the processes of adaptation and resistance inside prisons, are considered according to recent transformations of the correctional apparatus (spatial ethnicization, differentiation of treatment circuits and new forms of surveillance) in order to verify their analytical validity. Referring to the classic studies of prison sociology and ethnography and to some of the most important European research studies in this field, this Introduction is aimed at constructing the thematic frameworks in which qualitative research on the Italian prison system has been developed over the last few years. Particular attention is given to the problem of accessing this peculiar institutional field and to the research methods utilized. A final reflection is oriented to identifying the conditions that could make prison sociology more relevant within the wider realm of general sociology.