In each culture the origins of civilization can be tied to the arising of one concept in the human mind: straight lines. Straight and perpendicular lines are not found in nature, so where did they come from? What shift in consciousness occurred around the globe that triggered the start of rectangular building methods and linear organization as well as written language, pyramid construction, mathematics, and art? Outlining the historical, psychological, geophysical, and neurological roots of the modern human mind, Calleman shows how studying early civilizations offers a means of understanding the evolution of consciousness.