Adaptive optics is introduced as a technology for dynamic correction of rapidly changing aberrations in optical systems. Its three major components—the wavefront corrector, the wavefront sensor, and the control system are defined, and the function of each is explained. The requirements for a wavefront corrector used in compensating atmospheric turbulence are established based on the Kolmogorov turbulence model. The shape of a deformable mirror’s influence functions is analyzed through the principles of solid-state mechanics. Major actuator types and various deformable mirror designs are described. Liquid crystal wavefront correctors are presented as an alternative technology for high-resolution wavefront correction. Finally, Alvarez optical components are introduced as a solution specifically designed to provide single-mode correction of predetermined aberrations.