In this companion to American Levels and Their Makers, Vol. I, the author presents that great rarity a book on patents that both illustrates the patents (in a size large enough to be useful) and explains them. Two hundred and ten level patents are pictured and explained here, with explanations keyed to the patent drawings. They illustrate the major and continuing contributions by L.L. Davis, Justus Traut, the Stratton Bros., and L.S. Starrett, among...