In preparing this treatise the author has had as an incitement the knowledge that there was very little information to be had on the treatment and working of steel of practical value to the gen eral mechanic. For this reason he is convinced that a practical book on the treatment and working of the metal as modern de mands necessitate, that is, in regard to heating, annealing, forg ing, hardening and tempering processes, cannot fail to» prove of interest and value to all mechanics who use tools or who are in any way engaged in the working of metals. When the fact is considered that tools made from the best grades of steel will not perform the work required unless they have been treated properly during the various heating processes, the value of a knowledge of the most satisfactory and approved arrangements and methods to the mechanic is at once apparent. With the object in view of giving to practical men a book treating and presenting this paramount subject in a clear, con cise and practical manner, the author has drawn upon a personal experience of many years, gathered all the information obtain able, eliminating all unnecessary and obsolete matter, and added all that is approved, up-to-date and authentic.