While the book is a history of countless technological developments spanning all of human time (itself revolutionary, since most accounts of technology before his had focused on the 19th century), the heart of it is Mumford's program to create a "life-sustaining technological order" that would reorient the essential economic processes in which technology is employed from capitalism to basic communism:
- Conversion: turning the environment into energy. Under capitalism, this process is inefficient; communal ownership of the means of production and agricultural fields, centralized planning, and economic regionalism could reduce the inefficiencies of market-managed, uncoordinated extraction and increase conversion.
- Production: manufacturing goods. Under capitalism, increased production means increased profits, which can be reinvested in more production facilities. Automation without respect for the worker leads to strikes and absenteeism, not to mention dehumanization. Communal ownership and centralized planning would coordinate production so that each region only produces what it needs, and re-developing manufacturing processes so they're more interesting to humans would shift the focus from quantity to quality. This combination would increase efficiency and reduce the average work week from 40 hours to 15-20.
- Consumption: capitalism drives consumption by using style, fashion, and poor workmanship to manufacture wants and desires. Mumford hates trendy clothes and thinks we should really just consume commodities (produced en masse) and a few luxuries (produced by smaller, specialized firms). Reducing consumption would reduce production, which (again) would reduce work hours and make more time for culture.
- Creation: This is the end goal of Mumford's balanced, centralized system of production and consumption: enough surplus leisure time from work for people to develop the humane side of society: technical inventions, art, history, science, theory, communication. The idea here is to socialize creation so that each individual adds to the collective pool of knowledge about the world we live in, that technology can be harnessed to sustain and better life rather than increase profits, and that everyone gets to guide future development.
Mumford's critique of technological development is thus also a critique of capitalism, and a call for a new social order that uses technology to communist/human, rather than capitalist/profit-driven, ends.