The author has followed the construction of a typical house from start to finish. The many problems confronting the carpenter are explained. Then, step by step, the solution of these problems with the use of the steel square is given. The difficult work of cutting and fitting the timbers is dealt with, just as it is met and handled in the actual building of the frame of this particular house. In every phase of the construction, the way in which the steel square should be used is carefully explained. Application of this tool to the job of marking off the necessary cuts on the material is shown by many clear illustrations. The inexperienced carpenter, as well as the experienced carpenter, will find in this "Illustrative Problem" the answer to many puzzling questions. From the laying out of the wall lines to the construction of the dormer, the steel square is a valuable aid.