This inquiry into the technical advances that shaped the 20th century follows the evolutions of all the principal innovations introduced before 1913 (as detailed in the first volume) as well as the origins and elaborations of all fundamental 20th centuryadvances. The history of the 20th century is rooted in amazing technical advances of 1871-1913, but the century differs so remarkably from the preceding 100 years because of several unprecedented combinations. The 20th century had followed on the path efined during the half century preceding the beginning of World War I, but it has traveled along that path at a very different pace, with different ambitions and intents. The new century"s developments elevated both the magnitudes of output and the spaial distribution of mass industrial production and to new and, in many ways, virtually incomparable levels. Twentieth century science and engineering conquered and perfected a number of fundamental challenges which remained...