The Smoot-Hawley Tariff Act of 1930 remains one of the most enigmatic pieces of legislation in the 20th century. Held by some to have caused the Great Depression, and by others to have worsened it, the Act’s underlying motives continue to be the subject of vigorous debate. For example, Dartmouth College economic historian and trade expert Douglas Irwin pointed to a political ploy on the part of the Republican Party to avert electoral defeat in 1928 by the Mid-West farm lobby.This book presents an alternative view, based in large measure on recently published studies. It is argued that the Smoot-Hawley Tariff Act should be understood as the Republican Party’s attempt at closing a widening output gap in the US, resulting from the widespread adoption of a new power transmission technology in the form of electric unit drive (EUD). Electric unit drive, by providing the wherewithal to increase machine speed considerably, resulted in productivity gains in the 40-100 percent range. Existing plant and equipment was now vastly more productive as a result of greater machine speeds. The book consists of six papers, five of which were previously published.