The smooth functioning of an ordered society depends on the possession of a means of regularising its activities over time. That means is a calendar, and its regularity is a function of how well it models the more or less regular movements of the celestial bodies - of the moon, the sun or the stars. Greek and Roman Calendars examines the ancient calendar as just such a time-piece, whose elements are readily described in astronomical and mathematical terms. The story of these calendars is one of a continuous struggle to maintain a correspondence with the regularity of the seasons and the sun, d