The annual rings of trees can be used to date and classify cultural and natural historical events. This book impressively describes how this method was developed and how it is still used today. It provides insight into the concepts and working methods of natural scientists in their quest for reliable chronologies from the early modern period to the present. Errors and methodological missteps, as systemic companions of lengthy and complex research processes, were inevitable. Therefore, the focus is placed on the dynamics of what has "become" rather than the statics of what has "been." The thematically broad and interdisciplinary presentation appeals not only to representatives of the life sciences and historical sciences but also to a wider readership interested in the development of a research method.