The Egyptian pyramids, fantastic, man-made mountains containing more than 25 million tons of quarried limestone erected in little more than a century, appear to be useless. Nevertheless, they must have been considered useful by ancient Egyptians, who expended an unbelievable amount of labor constructing them. Previous attempts have been made to explain the function of the pyramids as astronomical observatories, granaries, refuges from the Flood, or the work of visitors from outer space. Although Mendelssohn readily admits that the archaeological evidence proves that the pyramids served as royal mausoleums, he argues that this was not their main function. The discovery of the main purpose of the pyramids is the subject of this book.