Automated machinery, such as computer numerical control machines (CNM), require constant monitoring for accuracy and precision. Thus, a correct understanding of 'metrology' - the science of measurement - is essential to the successful running and maintenance of all automated machines, and especially CNC machines. This book presents the main methods and means for measuring and monitoring the accuracy of geometrical parameters for CNC and automated machines, including modern 'Coordinate Measuring Machines' (CMMs). Parameters such as straightness, perpendicularity, flatness, pitch, and yaw and roll, and so on are considered, presenting different methods and means for their determination. A particular focus is given to the analysis of ISO written standards of accuracy control, terms and definitions, and methods for evaluation of the results of measurement during performance verification. This book provides readers a useful, accessible introduction, with practical examples and guidance covering: the measurement systems and techniques for monitoring of processes, systems, and equipment; testing of geometrical accuracy parameters and their assessment; measurement and monitoring of scales and encoders, including standards of measurement for length and angle, circular scales, linear scales, and methods and means for vertical angle calibration; and future trends in machine monitoring and performance verification.