This book intends to build a bridge for the student and the young engineer: to link the rocket propulsion fundamentals and elements with the actual rocket engine design and development work as it is carried out in the industry. The book attempts to further the understanding of the realistic application of liquid rocket propulsion theories, and to help avoid or at least reduce time and money consuming errors and disappointments. This book was written "on the job" for use by those active in all phases of engine systems, design, development, and application, in industry.