This short article constitutes an introductory part the Special Section on State and Parameter Estimation Methods in Sensorless Drives. In the current issue of the journal the first part of this Section is published. Accepted articles are focused mainly on the state variables and parameters estimation for vector controlled induction motor drives, using different concepts, like different types of Kalman Filters (KFs) or Model Reference Adaptive Systems (MRASs). The Kalman filter was also proposed for Brushless DC Motor (BLDC). Also neural networks (NN) have been proposed for mechanical state variables estimation of the drive system with elastic couplings.