In the introduction to his new book Steven Johnson starts out by describing the ninth-century Book of Ingenious Devices and its successor, the 13th-century Book of the Knowledge of Ingenious Mechanisms by the Arab engineer al-Jazari. Here were books of extraordinarily advanced technology. The latter contained sketches of

float valves that prefigure the design of modern toilets, flow regulators that would eventually be used in hydroelectric dams and internal combustion engines, water clocks more accurate than anything Europe would see for 400 years…

But in both books, Johnson says, ‘the overwhelming majority of the mechanisms […] are objects of amusement and mimicry’:...