Æsop

Another online discovery from the Library of Congress: The Æsop for Children, including:

Æsop is important for cultural literacy. Among the phrases that are mysterious unless the stories are familiar: "wolf in sheep's clothing" (see above), "sour grapes," "the race is not always to the swift," "crying wolf!" "dog in the manger," "the goose that laid the golden egg."

A list of the fables with links to each of them.