The authors look back five hundred years and uncover a distinct pattern: Modern history moves in cycles, each one lasting about the length of a human life, each composed of four eras - or "turnings" - that last about twenty years and that always arrive in the same order. First comes a High, a period of confident expansion as a new order takes root after the old has been swept away. Next comes an Awakening, a time of spiritual exploration and rebellion against the now-established order. Then come...