The study of energetic particles in magnetic fusion plasmas is key to the development of the next generation of "burning" plasma fusion experiments, such as the International Thermonuclear Experimental Reactor (ITER) and the Demonstration Power Station (DEMO). This book provides a comprehensive introduction and analysis of the latest experimental data on how fast ions behave in fusion grade plasmas, featuring the latest ground-breaking results from world leading machines such as the Joint European Torus (JET) and the Mega Ampere Spherical Tokamak (MAST). It also details Alfvenic instabilities, driven by energetic ions, which could cause the stochastic transport of energetic ions. MHD spectroscopy of plasma via observed Alfvenic waves and called "Alfvén spectroscopy" is introduced and several applications are presented. This book will be of interest to graduate students, researchers, and academics studying fusion plasma physics. Key Features: Provides a comprehensive overview of the field in one cohesive text, with main physics phenomena explained qualitatively first Authored by an authority in the field, who draws on his extensive experience of working with energetic particles in fusion plasmas Is suitable for extrapolating energetic particle phenomena in fusion to other types of plasmas, such as solar and space plasmas