Locksmiths have been challenged for decades with trying to understand master keying. That's not surprising since master keying involves numbers...a non-concrete, mental concept which has eluded the masses for centuries. If you were not good with numbers as a kid and you felt lost in class...you are not alone. This book takes you by the hand – the ‘real people,’ and walks you through the steps, baby steps if you will, from beginning to advanced, without leaving you in the dust. So, don’t let the fear of numbers…and what they can do…stop you from truly understanding the basics of master keying. In a fun way, this book invites you down the road of master keying through simple explanations using terms, charts, examples, quizzes at the end of each section and a Final Exam of 50 questions to assess your learning. The Collection section is jam-packed with advanced master keying data. All this in 261-pages of information glory! This book gives you the basic logic to unleash the simplicity of a usually complex topic. Learn, increase your income and enjoy the ride. -William M. Lynk, CML, CPS, ICML, CAI, M.Ed.