Wave-particle interactions are ubiquitous in space plasmas and tell one important aspect concerning the behavior and dynamics of charged particles. The study includes a number of important phenomena: 1) interaction at the inner edge of the ring current, 2) high frequency emissions at the outer planets, 3) electrostatic bursts on auroral field lines and at comets, and 4) generation of electron comics. These studies use analytical theory numerical simulation, and properties of these interactions and hoe they relate to the overall dynamics of the Earth's magnetosphere. ***