The book "Power System Coherency and Model Reduction" offers a comprehensive analysis of interarea modes in large power systems and explains how reduced models can be developed using the coherence concept and selective modal analysis. It addresses both linear and nonlinear analysis methods and is aimed at researchers dealing with interarea oscillations and model reduction, as well as professionals in the field of energy engineering who wish to develop reduced models for studies and control designs. This technical book is a valuable reference for anyone seeking a deeper understanding of dynamics in power systems and looking to improve the efficiency of models.