If you are looking for the style changes in the Mustang over 50 years, this book covers it pretty well.
The Mustang represented smart product planning and design from the start, followed by superbly handled marketing. Ford's Mustang team effort used every vehicle-marketing tool in the toolbox: clever tease long before the new product went on sale, unprecedented publicity, simple but effective advertising, the stage at the World's Fair, movie placement, distribution of toy plastic models, and even a replica pedal car for the future's young drivers. With a little luck, it turned out to be a classic case of launching the right product at the right time, and Ford sold a million units in less than two years. Even today, the Mustang is revered as a symbol of American design, engineering, and the unrestrained spirit of the American people
