The Collected Works of Irving Langmuir, Volume 5: Plasma and Oscillations is an 11-chapter text covers the extensive research study of Langmuir in the field of gas discharges. This book specifically tackles oscillations in ionized gases. The opening chapters describe the plasma-boundary phenomena and the use of a probe to separate the primary electron beam from the scattered electrons. The succeeding chapters deal with the collisions between electrons and gas molecules, oscillations in ionized gases, and the interaction of electron and positive ion space charges in cathode sheaths. These topics are followed by discussions on the general theory of the plasma of an arc and the properties of metastable atoms and electrons produced by resonance radiation in neon. The concluding chapter provides experimental evidence that the secondary electrons originate from bombardment by metastable atoms. This book is of value to physical chemists and physical chemistry researchers.