Although first published nearly thirty years ago, this book remains up-to-date, intellectually stimulating and realistic. Unlike most texts in the field, it relates design closely to the science and mathematics that are students' chief concern, and shows their relevance. It shows how to make simple but illuminating calculations, and how to achieve the insight and the invention that often result from them. Covering design principles in depth, this is, and remains, an original book: although some of the ideas which were novel in 1971 are now widely accepted, others remain new.