Books on engineering design, like designs them selves, are highly individual. In this one, the author emphasizes the importance of a visual approach to machine design and makes his point by including a large number of illustrations. He also stresses the need for clear objectives in all design work. Professor Leyer is an experienced designer and an inspiring teacher, and his book is based on his own lecture course in the subject. Throughout, he shows be the goal to which mathematics, mech design to anics and engineering drawing are the means. His book complements the usual range of engineering texts and can be read to advantage by students at any stage of their studies. In addition, he gives clear descriptive accounts of some important topics (such as stress concentration and the torsion of non circular sections) which are often omitted from textbooks because of their mathematical complexity. In controversial matters-the merits of the patent system, for example-Professor Leyer leaves us in no doubt as to his own views. In editing this translation I have used SI units for physical quantities and I urge readers to make their own calculations in this system whenevet they have the choice. It will be some years, however, before the familiar inch, foot and pound disappear alto gether and I have added the corresponding values in these units.