A comprehensive work with descriptions of 336 Eastern and Western astrolabes and astrolabe clocks, and a 23 page bibliography. Gunther also reprints William H. Morley's Description Of A Planispheric Astrolabe, Constucted For Shah Sultan Husain Safawi, King Of Persia (London, 1856), which was originally published in a limited edition and Gunther describes as: "by far the best monograph upon the instrument, and, as only 100 copies were printed, it has never had the wide circulation it deserved ... It is, however, perhaps the most scholarly work on the Astrolabe ever published" (p. vi).