This book explains how for thousands of years, the effort to measure time & to create a workable calendar was one of the great struggles of humanity, a conundrum for astronomers, mathematicians, kings, priests, & anyone else who needed to calculate for the harvest, tax collection, or religious sacrifices. Human beings have always been & still are struggling to count the days & weeks & years, to calculate the movements of the sun, moon, & stars, & to capture them all in a grid of small squares that spread out like a net cast over time. How this net was woven in different cultures over the millennia, & why, is the subject of this book. Illustrated.