v. 1. The golden interlude, 1900-1910 -- v. 2. The clamorous era, 1910-1920 -- v. 3. The roaring twenties, 1920-1930 -- v. 4. Hard times, 1930-1940 -- v. 5. The patriotic tide, 1940-1950 -- v. 6 Shadow of the atom, 1950-1960 -- v. 7. Winds of change, 1960-1970.