This book is the result of research conducted in Polish post-criminal isolation units related to the accessibility of religious practices and services for people incarcerated there. The study covered individuals from 35 units, including prisoners from 15 penitentiary facilities and 4 detention centres, as well as juveniles from 8 youth educational centres and 8 correctional facilities. The research also involved educators from those units who presented the religious life of convicts and detainees from their own perspective. The empirical part was preceded by considerations on the social and individual significance of religion and an outline of international and national (Polish and German) standards of religious freedom, including in post-criminal isolation units.