Although on the surface, toyota’s development process seems extraordinarily cumbersome, it is a model of how to make better cars more quickly and cheaply. Toyota’s engineers and managers delay decisions and give suppliers partial information, while exploring numerous prototypes. The authors examine what they call “set-based concurrent engineering,” a method prevalent at Toyota but not at other Japanese and U.S. automakers. Toyota designers think about sets of design alternatives, rather than pursuing one alternative iteratively. They gradually narrow the sets until they come to a final solution. Through extensive research, case studies, and interviews, the authors present their argument – that this apparently inefficient system has made Toyota the fastest and most efficient developer of autos.