Cyclotron Waves in Plasma is a four-chapter text that covers the basic physical concepts of the theory of cyclotron waves and cyclotron instabilities, brought about by the existence of steady or alternating plasma currents flowing perpendicular to the magnetic field. This book considers first a wide range of questions associated with the linear theory of cyclotron oscillations in equilibrium plasmas and in electron plasmas in metals and semiconductors. The next chapter deals with the parametric excitation of electron cyclotron oscillations in plasma in an alternating electric field. A chapter focuses on plasma turbulence, which results from the development of cyclotron instabilities. The last chapter discusses pertinent experimental data concerning cyclotron waves in plasma. The book is intended for specialists in plasma physics and a number of related fields, including the physics of the ionosphere, solar wind and, metals, as well as for students and teachers who are specializing in these subjects.