The Asahi Optical company rightly claimed that the history of Pentax cameras is the history of the 35mm SLR. More than any other manufacturer, Asahi has been responsible for the 35mm SLR becoming the universal camera for all serious amateurs and many professionals. They pioneered many of the technical advances that make the SLR the near perfect instrument it is today. This story is told by Danilo Cecchi through the many models produced during nearly forty years.