The exploration of water names received new impulses after 1945 through the work of the Indo-Europeanist Hans Krahe, which led to the systematic documentation of German water names in the project "Hydronymia Germaniae" (1960-2005) and sparked active research activities. The insights gained from this work regarding the great age of many water names in Central Europe, their particular cultural-historical value, their linguistic structure, and their etymology have so far only been accessible in purely scientific publications. The German Water Name Book aims to make the research findings available to a broad audience of non-experts in the form of an etymological name book. An introduction informs readers about the ways in which German water names have been formed throughout history, the motives for naming, and historical aspects.