This book provides specific, practical advice for engineers who are advancing beyond their technical specialty and find themselves working with other specialties necessary to the development of a complex system or product. They continually face a variety of issues that were invariably never addressed in their schooling: dealing with specifications, project plans, and budgets; improving quality by working with "downstream" functions such as production and service; resolving incompatibilities and bugs under a variety of test conditions; providing technical direction and reviews; and more. Based on "lessons learned" by the author over a forty-year career developing complex systems products, the book presents basic principles that are applicable whether you are in a bureaucratic, multi-national corporation or one with the founder still in control. This book is concise, but the content is dense. As such, it will also provide a succinct refresher for more experienced professionals and their management when facing challenges.