If you're willing to accept that metaphorical sword of knowledge, then Harley-Davidson Knucklehead: Eighty Years is definitely for you. You're sure to be the envy of your friends when you win the bet as to who can name the most factory color options from 1936 (hint: there were 5). But wait, there's more! A lot more, actually — almost 200 pages of facts about production costs, model differences, aftermarket options and so on. Not only that, but incredible, high-resolution shots of everything from original-paint production models to the streamlined EL-powered racer that set the speed record on a Florida beach in 1937.