The Apostolate of the Sick is a community established in the Netherlands in 1925. The principal purpose of the community, which is present in Poland as well, is to discover a spiritual and religious meaning of life marked by sickness and suffering. The monograph is the first comprehensive study of theology that underpins the foundations of the community since the beginnings of the Apostolate of the Sick. It has been based on Dutch, Polish, and French sources. The monograph proves that recognition of the meaning of suffering, often after an extended internal struggle, is extremely important for the sick. They are no longer passive receivers of care but become spiritually active entities. Such an attitude does not imply martyrdom nor does it diminish the achievements of medicine. Instead, it constitutes a spiritual and moral barrier against euthanasia.