The three-part basic concept of the series (Presentation - Fundamental Problems and Trends in Research - Sources and Literature) does not need to be discussed here. The concept is so compelling and practical that the Oldenbourg series has long been able to hold its own effortlessly against other study book series, which are now known to exist in large numbers. In addition to the conceptual framework, the fact that it has been possible to consistently engage recognized experts as volume authors has also contributed to the series' leading position. These experts are able to provide a concise overall presentation and a focused examination of the essential problems within the tight scope guidelines.