This book goes into great detail of what I consider the best X-Plane of them all, the X-15. This X-plane was the last of the Manned Rocket planes, it went beyond Mach 6, and if the project had continued, would I am sure have passed Mach 7. The X-15 reached the edge of space at 380,000 feet altitude. The project was the first by North American, as they won the contract over Bell and Douglas, who had until this been the main developers of the X-Planes.
There is a lot to the story of the X-15, and this book goes into a lot of detail in an informative and entertaining way. The book draws you in and keeps your attention. I read the book in one sitting and enjoyed it greatly. The book covers all the issues and problems, alongside the great steps forward, the X-15 helped achieve, and the advances in systems, airframe, engines, and materials.