This paper describes an outline of fuel cells which are currently under development as the Moonlight Project of Japan. Fuel cells of phosphoric acid type, of molten carbonate type and of solid electrolyte type are all explained for the following items.
(1) Principles and characteristics of each fuel cell
(2) Components and systems of fuel cells
(3) Present state of research and development
(4) Reform of fuel
(5) Future R & D plan and application fields
