This is a textbook about rocket engineering, concentrating on the nitrous oxide hybrid rocket engine, both small and large. It's also a book about the science of chemical rockets in detail: three of the chapters are full of in-depth rocket science describing how all chemical rockets work. After a first chapter brushing up on the science and maths you'll need, the book describes the choice and safe use of hybrid rocket propellants, and how they're handled in practice. Then there are the rocket science chapters. Then you learn how to design, construct, and operate, a large hybrid rocket engine capable of getting you into Space. The book also includes a practical guide to the testing of hybrid rocket engines large and small, and how to fly them safely. Included are full instructions for programming a rocket trajectory simulator in Microsoft Excel, and several appendices containing rocketry information and equations, and instructions on how to design a bell nozzle.