Mr. Lopez reinterprets the civilization of the High Renaissance in Italy as a dramatic succession of three ages: Youth, 1454-1494; Maturity, 1494-1527; Decline, 1527-1559. In the first period, political and economic stabilization brings forth a mood of confident expectation which expresses itself in literature, art, and philosophy, all reaching for a goal of "self-centered aesthetic harmony." In the second period, a series of foreign invasions...