This introductory account of instabilities in plasmas concentrates on laboratory plasmas, such as those encountered in fusion research, and the space plasmas studied in physics of the magnetosphere and solar atmosphere. This account bridges the gap between a graduate textbook on plasma physics, and specialized similarities between astrophysical and laboratory plasmas that are traditionally regarded as quite separate. The author, an expert in plasma astrophysics who has written a two-volume book on the subject, treats the material naturally, lending a broader perspective to the subject. This is an instructional text for graduate students and professionals in magnetospheric and mathematical physics, radiophysics, solar and theoretical astrophysics and radio astronomy.