Intended for drafting students in engineering drawing classes, the text provides basic definitions and explanations, as well as sample illustrations to be used as guides in dimensioning class projects by this technique. The content is divided into three units plus an appendix. Unit 1 discusses basic concepts, including the importance of the system; unit 2 covers tolerances of form, and unit 3, tolerances of position. The units are subdivided into lessons. Each lesson states an objective, gives related information (if any), discusses the topic with the aid of accompanying illustrations, and concludes with assignments for the student. These assignments are questions based on the material covered in the lesson and also frequently require the student to perform calculations or draw sketches. Appended are conversion and comparison charts to aid the student in the completion of assignments. (RG)