The Knucklehead model has an enormous importance for the motorcycling sport in general and for the Motor Company in particular. It is an outstanding example of American engineering. In 1936, in times of an economy suffering from the Great Depression, the four founders had the courage to come out with an OHV motorcycle that soon should become a milestone in the history of Harley-Davidson. Model year after model year this book describes the detailed technical development of the Knuckleheads. Excellent picture material complete the information provided and make this book a most useful source for both restorers and enthusiasts.