Of the origin or antiquity of the art of sheet-metal working the author knows very little; and although he realizes that the marvelous numbers of ingenious tools and devices which are used to — day to produce articles ranging from the modest trouser button to the massive boiler head are but the results of a long course of evolution, he is convinced that a treatise describing the tools and devices of the present day is what the practical man wants. Although the origin and history of Obsolete methods and tools may be of interest to the antiquary, the present-day machinist prefers to spend his hours of leisure in acquainting himself with the design, construction and use of tools with which he may in crease the output and lower the cost of production, and thereby increase his earning capacity. With this object in view, and trusting that all metal-working mechanics may be helped by it, this book is modestly submitted to the public.