The Century Dictionary, produced under the supervision of William Dwight Whitney who for many years was a Professor of Philology at Yale and has long been regarded as among the greatest achievers of American lexicography. First published in six volumes (1889-91), it evolved into a twelve-volume edition (1911) including supplementary volumes, a Cyclopedia of Names, and a world atlas. The later editions run to more than 8,500 three-column pages and contain more than 200,000 main entries with over 500,000 definitions. The Century is particularly noted for its etymologies, its thorough coverage of American English, its emphasis on scientific and technical terms at a time when such terms were relatively neglected by other dictionaries (including what came to be known as the OED), and its many beautiful illustrative engravings and quotations. Indeed, it remains remarkably "usable" as a dictionary to this day.