Everybody knows the idea, now usually humorous, that some people have more accidents than other people. Accident proneness was once a technical term, used to separate some people, identified as accident prone, from dangerous situations. The idea rose and fell from the early to the late twentieth century. It moved from Germany and Britain largely to the United States. But the story of accident proneness also reveals an ugly underbelly of technological development: accidents as humans encountered machines. Accident Prone is a book about technological change, about damage to bodies and property, about implicit social systems. It is a work pioneering the field of the history of accidents.Technology demands uniformity. People, however, differ individually. From this disjuncture came “misfits of the machine age,” who did not adapt to the machines. The idea of accident proneness for decades helped to identify those people. But in the post-industrial age, engineers and psychologists together worked on technology to make the devices and systems reduce risk. They did not see that they were part of a grand social shift that, as this book points out, has now become obvious.