This book is dedicated to the idea that engineering design is problem solving-science-based problem solving with social-human awareness. The author has abstracted three general skills from an analysis of the design problem-solving inventiveness, analysis, and decision making. Each of these has been made the subject of special attention in its own part of the book. The book is the result of teaching design to seniors in mechanical engineering at both Purdue University and Swarthmore College. Experience with these courses led the author to the conclusion that his students knew more than they understood or could use. He took it as his task to help them learn how to use purposefully what they had been taught in their science and engineering courses. There was little doubt that they way they had been taught was interfering with their ability to use what they had learned. Hence, the author set out to discover the general skills used in design problem solving so that each could be explicitly taught. It is to this end that this book is contributed as a beginning.