This book presents the latest information on the intelligent CNC machine tool spindle system, which integrates various disciplines such as mechanical engineering, control engineering, computer science and information technology. It describes a prediction method and model for temperature rise and thermal deformation in motorized spindles and proposes an intelligent stator resistance identification method to reduce the torque ripple of motorized spindles under direct torque control. Further, it discusses the on-line dynamic balance method for NC machine tool spindles. The biogeographic optimization algorithm and hybrid intelligent algorithm presented here were first applied in the field of motorized spindle performance control. In turn, the book presents extensive motorized spindle performance test data and includes detailed examples of how intelligent algorithms can be applied to motor spindle stator resistance identification, temperature field prediction and on-line dynamic balance. In summary, the book provides readers with the latest tools for designing, testing and implementing intelligent motorized spindle systems in terms of the basic theory, technological applications and future prospects, and offers a wealth of practical information for researchers in mechanical engineering, especially in the area of control systems.