The unique contribution the historian of technology and society can hope to make is to inject a chronological dimension. Hence historians are not likely to fit well among those who see technology either as an unalloyed blessing or as an unmitigated curse. Historians have, despite a lack of firm methodological assumptions, been piling up empirical evidence that technology has been a well-recognized factor in social change not only back to the Industrial Revolution but also back at least to Olduvai Gorge and the end of the Pleistocene glaciation. However, the most unlikely conclusion they could possibly draw from this chronological sequence is the one which Mesthene attributes to them-that technology as such is not worthy of special notice. Perhaps the econometricians have rubbed out the acceleration of productivity since the 1880s and have denied a change in time period between invention and adoption of technological components in recent decades. The historian is interested in precisely those social, cultural, psychological, and political effects which render the conclusions of the econometricians elegant exercises, beautiful in their way but divorced from the choices which men and women fixed in time have always had to make. For the understanding of contemporary society, technology is worthy of such special notice that a program on technology and society cannot afford to overlook the possibility that important elements in the present interaction between technology and society took shape long before the 20th century. Even if one accepts Mesthene's proposition that the contemporary situation is qualitatively different from that of past societies, the way is still open to use the new insights our present technology and plight give us to reexamine the past with eyes better focused to understand the nature of technology in its interactions with society in any period. Two leading ideas of the present scene-the systems approach and ecological balance-have the possibility of combining to elucidate the nature of technology and innovation, but these ideas need a long time span to test themselves adequately.