A rigorous appraisal of sundial science includes mathematical treatment and pertinent astronomical background, plus a nontechnical treatment so simple that several of the dials can be built by children. 106 illustrations.

What Froude says of history is true also of astronomy: it is the most impressive where it transcends explanation. It is not the mathematics of astronomy, but the wonder and the mystery that seize upon the imagination. The calculation of an eclipse owes all its prestige to the sublimity of its data; the operation, in itself, requires no more mental effort than the preparation of a railway time-table. The dominion which astronomy has always held over the minds of men is akin to that of poetry; when the former becomes merely instructive and the latter purely didactic, both lose their power over the imagination. Astronomy is known as the oldest of the sciences, and it will be the longest-lived because it will always have arcana that have not been penetrated.

The Adler Planetarium & Astronomy Museum in Chicago is home to one of the world's great collections of astrolabes. Roderick and Marjorie Webster, Adler Curators Emeriti, present the Western astrolabes from the Adler's collection. The earliest of these instruments dates from the 13th century, others are from the workshops of the greatest craftsmen of the Renaissance. All are described here and illustrated lavishly with photographs showing the front, the back and additional details such as the maker's signature. Introductory essays by the Websters and Sara Schechner Genuth explain the use of the astrolabe and its role in cultural and social history, while the appendices and bibliography provide information essential to the specialist.