Immediately following the Second Vatican Council, participating council theologians and experts, under the patronage of Cardinal Joseph Frings and Archbishop Hermann Schäufele, set about processing, illuminating, and commenting on the constitutions, decrees, and declarations of the council. This comprehensive and theologically groundbreaking commentary on the council laid the foundation for the practical implementation of the council's resolutions. Fifty years after the council, this unique volume serves as an essential collection of sources for understanding the Second Vatican Council. This edition finally makes this incomparable document accessible again. Alongside the original Latin texts and their German translations with commentary, it includes an introduction to the council and a detailed council chronology, presenting an unparalleled historical testimony.