Suleyman defines a "wave" as a cluster of related technologies converging in the same period and completely changing how society works. He estimates that there have been about twenty-four such waves in human history, from agriculture and bronze to electricity and the internet.

These "general-purpose technologies" have especially wide uses and keep spawning second- and third-tier inventions, their effects compounding layer upon layer. Agriculture, for example, let people store grain, settle down and begin to divide labor, which brought more inventions and more population.

Waves usually take off when two conditions are met: several technologies mature at once, and prices fall to what ordinary people can afford. The book gives Ford's assembly line as an example, which cut the price of a car from two thousand dollars to eight hundred fifty, and by 1930 59% of Americans owned a car. Computers are the same: from vacuum tubes and transistors to integrated circuits, personal computers and smartphones, chip density has roughly doubled every two years.