As a professional involved in reviewing and testing mechanical locks for several manufacturers, I have over time gained considerable knowledge about locking techniques and systems and was initially skeptical about this book. As soon as I started reading my perceptions changed. There were several locking techniques I had not seen or read about before. In addition, not only were many locks covered in great detail, but many uncommon locks too. There are certainly many ways one can talk about a lock, from patents to operating principles, or even how to manipulate the. In my opinion, the author has done a remarkable job at covering the subject of mechanical locks in an understandable and comprehensive manner. I would recommend this book to every lock enthusiast or industry person who would like to dive deeper into locking techniques.