This volume contains the results of many years of investigations of pulse gas-discharge lasers carried out at the Optical Laboratory of the Lebedev Physics Institute in Moscow. The two papers report mainly experimental results obtained in studies of pulse lasers utilizing translations in metals (Isaev and Petrash) and electronic transitions in diatomic molecules (Kaslin and Petrash). Population inversion mechanisms and the principal properties of the lasers are considered. v CONTENTS Investigation of Pulse Gas-Discharge Lasers Utilizing Atomic Transitions A. A. Isaev and G. G. Petrash Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 §l. Efficiency in a Gas-Discharge Laser. • . • • • . . . . . • • • . . • • . • . . • . • . • . 1 §2. Review of the Literature • • • • • • • . • • • • • • . . • • . . . • • • • . • • • • . • . . . • 4 Chapter I. Kinetics of Output Power Saturation in a Three-Level System. • • • • • • • • 6 §1. Level Populations and Saturated Power in a Three-Level System. • • • • • • • • 7 §2. Absence of Decay of Laser Levels. • • • • • • . • • • • . • . • . • • • • • • • • • • • • • 8 §3. Decay of Laser Levels by Emission of Spontaneous Radiation. • • • • .