Since the activities of General Motors Corporation have been primarily in the automotive field, illustrations of these engines have not been included in the present work. Obviously, General Motors has been and still is building a great variety of large diesel engines. These are however of a more or less modern nature and would usurp a large portion of this work and force total exclusion of many smaller companies. The reader is referred to many different works covering FM automobiles in particular, the Crestline Automotive Series.