The Subsynchronous Resonance (SSR) is a phenomenon related to the interaction between the electric side and the mechanical side of the electric grid. This book introduces a comprehensive approach to the analysis of SSR. The analysis includes the real-time modelling of the synchronous machines, transformers, and different power system components. Through this book the various types of SSR oscillations have been studied and the appropriate mitigation algorithms have been used as well as the adaptive control techniques. To further study the effect of different design parameters on the SSR, the parameters of the synchronous machine have been modified and studied using Eigenvalue technique and time-domain parametric analysis. The authors of the book would present their gratitude and appreciation to Prof. M. A. L. Badr from Ain Shams University due to his continuous help and encouragement to finish this book.