It is customary to speak of his best known short stories as fairy tales; wonder-stories is in some respects a more exact description, but the name has hardly a native sound. Andersen himself classed his stories under the two heads of _historier_ and _eventyr_; the _historier_ corresponds well enough with its English mate, being the history of human action, or, since it is a short history, the story; the _eventyr_, more nearly allied perhaps to the German _abenteuer_ than to the English _adventure_, presumes an element of strangeness causing wonder, while it does not necessarily demand the machinery of the supernatural. When we speak of fairy tales, we have before our minds the existence, for artistic purposes, of a spiritual world peopled with beings that exercise themselves in human affairs, and are endowed in the main with human attributes, though possessed of certain ethereal advantages, and generally under orders from some superior power, often dimly understood as fate; the Italians, indeed, call the fairy _fata_. In a rough way we include under the title of fairies all the terrible and grotesque shapes as well, and this world of spiritual beings is made to consist of giants, ogres, brownies, pixies, nisses, gnomes, elves, and whatever other creatures have found in it a local habitation and name. The fairy itself is generally represented as very diminutive, the result, apparently, of an attempted compromise between the imagination and the senses, by which the existence of fairies for certain purposes is conceded on condition they shall be made so small that the senses may be excused from recognizing them.