This book is a comprehensive introduction to the rapidly developing field of modeling and characterization of PEM fuel cells. It focuses on i) fuel cell performance modeling and performance characterization applicable from single cells to stacks, ii) fundamental and advanced techniques for structural and compositional characterization of fuel cell components and iii) electrocatalyst design. Written by experts in this field, this book is an invaluable tool for graduate students and professionals. * Part I covers fundamentals and advanced techniques for the structural and compositional characterization of Pt-based and PGM-free PEM Fuel Cells. * Part II focuses on fuel cell performance modeling and advanced techniques for performance characterization. * Part III reviews the design of electrocatalysts and discusses applications in PEMFC.