Humanity deviated from natural time 5,000 years ago. The 12-month Gregorian calendar and the 60-minute hour of the mechanical clock have subjected us to the artificial 12:60 frequency that governs what Arguelles calls the technosphere. This long-awaited sequel to The Mayan Factor argues that 9/11 is a signal that if humanity is to survive and avert ecological catastrophe, we must change our definition of time and return to a natural harmonic calendar based on the 13-moon 28-day cycle. With 38 color and b/w illustrations. September.