Archivists the world over have organized their folktale collections according to Aarne's eminently practical system of classification. Folktale scholars have published dozens of type indices of folktales collected from specific countries or language areas.
Aarne was first introduced to the research, collection, and publication of folktales under the tutelage of Kaarle Krohn at the University of Helsinki. Aarne later pursued his study of the folktale in Russia, Germany, Denmark, and Sweden. He earned his doctoral degree in 1907 and went on to become a professor of folklore in 1922. When Aarne was writing his doctoral dissertation, Comparative Studies of Folktales, 1908, he was struck by the difficulty of acquiring research materials from other countries. He began preparing a catalogue classifying folktales that were represented in the oral tradition of several European countries. As his base material, he used Finnish folktales (more than 25,000 texts), the Danish folktale collections of Svend Grundtvig (about 850 texts), and Grimms' Kinder- und Hausm€archen (210 texts).
Aarne divided folktales-which he designated with term “m€archen”-into three subgenres:
- animal
- ordinary folktales
- jokes and anecdotes
He also distinguished each type of folktale plot with a name, number, and a brief description of its contents. For example, the ordinary folktale about the strange little man (Tom Tit Tot, Rumpelstiltskin) who helps a girl spin gold from straw was called The Name of the Supernatural Helper and given the tale-type number 500 (which would be known in the standard practice of folklorists as Aa 500, later as AaTh or AT 500, and most recently as ATU 500). The story is a typical representation of the subcategory that Aarne called “tales of magic”. The other subcategories of ordinary folktales identified by Aarne are (as rendered into English by Stith Thompson): religious tales, novellas or romantic tales, and tales of the stupid ogre.
In 1911, Aarne published his index of Finnish folktales, The Finnish Folktale Variants. Aarne based his investigations of the folktale on the historic-geographic method. He published numerous monographs in which he analyzed and outlined the distribution, variation, and history of individual folktales. His studies often led him to conclude that a given folktale's starting point was in India, thus lending credence to Theodor Benfey's vision of the genre's primal home. Aarne outlined his research methodology in his handbook Guide for the Comparative Investigation of Folktales, 1913.
Aarne's most enduring achievement, however, is his folktale index. The international taletype index proved to be so useful that there are now three expanded editions. Stith Thompson compiled the first two in 1928 and 1961. The latest, The Types of International Folktales:
A Classification and Bibliography (2004), is a three-volume edition by Hans-J€org Uther.
