What makes the true walnut (Juglans regia) such an enticing topic? For the author, it was initially the suspicion that the economic potential of walnuts in Germany is far from being fully realized. The fact that there are only a few German studies and publications on the subject, along with the curiosity to find out why walnuts have slipped into the background of agricultural and forestry efforts, served as the starting point for her master's thesis at the Eberswalde University for Sustainable Development. With the conclusion that walnuts have a high conservation value in Germany and that their cultivation simply needs to be revived, the author decided to make her master's thesis accessible to a broader audience. The fascination with the walnut tree is by no means new; rather, it has a long tradition.