The first three volumes discussed the topics religion, revelation and church. The fourth of this series offers now a historical insight into the doctrine of the Trinity. Wenz explains brilliantly the preconditions of a Christian God and His classic expression in the doctrine of the Trinity and makes therefore this study suitable for students in the main course. The history of Israel as well as the teachings of the Hebrew Bible and the Ontotheology of ancient Greek philosophy form the basis of this book. Special emphasis is put on the development of monotheism.