The Aarne–Thompson–Uther Index (ATU Index) is a catalogue of folktale types used in folklore studies. The ATU Index is the product of a series of revisions and expansions by an international group of scholars: Originally composed in German by Finnish folklorist Antti Aarne (1910); the index was translated into English, revised, and expanded by American folklorist Stith Thompson (1928, 1961); and later further revised and expanded by German folklorist Hans-Jörg Uther (2004). Along with Thompson's Motif-Index of Folk-Literature (1932), with which it is used in tandem, the ATU Index is an essential tool for folklorists
