A detailed and analytical study of the structure of the Egyptian calendar which was the product of science and religion; the calendar was based on an in-depth astronomical knowledge but evolved around mythology. Von Bomhard describes how the year was divided into three agricultural seasons, each comprising four months of thirty days, which were followed by five extra days, and argues that Egyptian scientists chose to ignore leap years and instead viewed their year as part of a perfect cycle that would complete itself in 1460 years. This reflects both the importance of the seasons to life by the Nile and the Pharaonic obsession with eternity. This is a complex treatise that is supplemented with numerous calendars depicted in tombs, temples, inscriptions and papyri, as well as astronomical and mathematical diagrams.