CONSTRUCTIVE criticism of automobile bodies as now built is given herein, based on experience gained in driving five-passenger sedan cars of many makes a total distance of nearly 10,000,000 miles in one year in tests at the General Motors Proving Ground. The fault finding, although humorously exaggerated, will be valuable if taken seriously, as it gives to all body designers and builders the benefit of testing experience that few companies are in a position to gain at first hand. The author treats his subject from the viewpoint of the abstract customer; that is, the automobile-purchasing public as a whole and as represened by the imaginary average man, who is assumed to have average stature and body structure and to drive all the different makes of car. Thus he is assumed to change from one to another make frequently, instead of becoming used to only one or two cars. Factors that influence the initial and the repeated purchase of a car are given in the order of their importance, and the index by which the customer measures the merit of the car is said to be the maximum satisfaction he has experienced with each individual characteristic in all the other cars he has driven. In other words, the best in all cars is his basis of comparison of the individual car and body, and he can be completely satisfied only if one car is as good in every respect as the best that has been found in any car for that particular feature. Standardization of fundamental dimensions based on the measurements of the average figure of all drivers is indicated as a need of primary importance. Strictures are laid on various bodies because of interference with vision in front and through the rear window, because of squeaks and rattles and many other details that, because they are constantly evident to eye or ear, are more annoying than faults of the chassis. No attempt is made, however, to set up specifications for a body that will give complete satisfaction to various classes of user.