Almost everything of a theoretical nature has been avoided, so as to bring its utility within the grasp of those workmen who have not had the benefit of a common school education, and within the understanding of every apprentice boy. It has been deemed necessary to introduce a chapter on the formation of geometrical figures, so as to give the reader the necessary knowledge required to construct understandingly the figures that follow in the work; but everything of a mystifying nature has been kept out, so that it is hoped the reader will not get frightened at the threshold and drop the book because of the geometrical figures that con front him. It must be borne in mind that all figures described by pen or pencil, that have for their object the delineation of roofs, house plans, bridges, or other like work, are composed of geo metrical combinations, and every mechanic has to meet these combinations every day, in some shape or other, when pursuing his regular occupation, and it is therefore quite necessary that he should know something of the principles that underlie the con struction of the drawings he works after. It need hardly be said here that the material for this work has been drawn from a large number of sources, as anyone at all conversant with the science of carpentry and joinery will readily discover that such has been the case. Nearly every work of im portance, from those of Nicholson down to Newland and Hatfield, has been consulted and drawn from to make the work now pre sented. Thanks are due the publishers for their liberality in keeping the price of this book — which is necessarily an expensive one to publish — at a sum which places it within the reach of every workman in the country.