The Wörterbuch der ägyptischen Sprache (Dictionary of the Egyptian Language), abbreviated Wb in bibliographic references,[1] is a large German-language dictionary of the Egyptian language published between 1926 and 1961 by Adolf Erman and Hermann Grapow. It is a comprehensive work encompassing 3000 years of linguistic history, including Old, Middle, and Late Egyptian as well as hieroglyphic inscriptions of the Classical Greco-Roman period. The dictionary contains approximately 16,000 headwords in five main volumes, two secondary volumes, and five volumes of primary source references.[citation needed] It is therefore the largest and most complete printed dictionary of Ancient Egyptian in existence.[2]