Glenn Porter notes in his forward that Hounshell demonstrates the spread of "mass production technologies":

The techniques were spread and improved by a close-knit network of key mechanics, who moved out in concentric circles from the armories to the machine tool companies, the sewing machine manufacturers, and the rest, all the way to the automobile makers. (p. xv)

Others have discussed mass production as a twentieth century phenomenon, and they have pointed vaguely to Eli Whitney as the "father" of mass production. What Hounshell has done is map the trajectory through the 19th C to the 20th in a comprehensive way.

Starting in his "Introduction," Hounshell traces the historiography of mass production techniques and situates himself within it. Starting with Robert S. Woodbury's T & C essay that showed Eli Whitney was not the originator of mass production, he then discusses the role of Merritt Roe Smith's work on the Harper's Ferry armory. Nathan Rosenberg he credits with putting an emphasis on machine tool industries as a key means of distributing know how throughout the land. Hounshell differs from Rosenberg in that he argues this distribution of knowledge was halting and proceeded in fits and starts. The spread of mass production technology, according to Hounshell was uneven and coexisted with older technologies throughout. As Roe Smith points out in his review, "the impression one comes away with is how bumpy and twisted the path of technological progress really is." (p. 160)

In "The Sewing Machine and the American System of Manufactures" he describes how the Wheeler and Wilson company adopted "armory practice" well before I M Singer & Co. did. Singer relied on older craft practice into the 1880s, purposely marketing the machines as the best money could buy and selling them at a premium. The "armory practice" employed by Wheeler and Wilson evidently did not mean cheaper machines mass produced would capture the market, since they were absorbed by their higher priced (up market) competitor Singer in the 1860s.

In "The McCormick Reaper Works and American Manufacturing Technology in the Nineteenth Century," he describes how Cyrus McCormack followed the same strategy as Singer, selling the best product money could buy at a premium price. McCormack, even more than Singer relied on craft methods and advertising to dominate their market sectors, not on armory practice. The annual need to come out with new models foiled the attempts of Cyrus McCormack, Jr. to introduce armory methods of production. Rather than reapers or sewing machines as the site for transfer of armory practice to mass production, Hounshell points instead to the bicycle industry.

In "From the American System toward Mass Production: The Bicycle Industry in the Nineteenth Century," he describes how the bicycle industry started to use stamped sheet metal parts to assemble their product. Albert A. Pope's Columbia bicycle "was made by methods growing directly out of the New England armory practice and refined by sewing machine manufacturers," however these machines weren't sold at the lowest price -- rather they were the most expensive bicycles in the industry!

It wasn't until Henry Ford's Model T that products made with armory methods were sold at the cheapest possible price. In a chapter entitled "The Ford Motor Company and the Rise of Mass Production in America," he explains how it was that "together, armory practice [here the creation of fully interchangeable parts] and sheet steel work equipped Ford with the ability to turn out virtually unlimited components. It remained for the assembly line to eliminate the remaining bottleneck - how to put these parts together. " (p. 10) He then considers the limits of mass production in a chapter called "Cul-de-sac: The Limits of Fordism and the Rise of Mass Production in America." By the 20s Ford ran into the need to implement a more flexible form of mass production and was forced to bend to the consumer's desire for more variety in the cars they chose.

Hounshell ends the book with a concluding section on critiques of the "ethos" of mass production, which held that men could be mechanized too. As Merritt Roe Smith mentions in his review, this last section seems somewhat disjointed from the remainder of the book. As a historian of technology, Hounshell is a master -- as a historian of cultural criticism, he is a little less convincing.