The term Adaptive Optics (AO) describes the active control of an optical device to remove distortions caused by aberrations in an optical beam path. An AO system enables beam forming and image correction in the presence of distortions and atmospheric effects. Major obstacles in imaging through the atmosphere include extended source/target anisoplanatism, distributed strong turbulence, scintillation, and branch points. Many applications have requirements for which the generation of a wavefront sensing source via the projection of a laser is undesirable or unfeasible. A variety of AO compensation techniques exist and have been demonstrated in the field, each with specific merits and disadvantages. A survey of the many types of AO control is presented. Common AO techniques include Classic Adaptive Optics, Multi-Conjugate Adaptive Optics (MCAO), and Extended Source AO (also known as correlation wavefront sensing). More recent applications include Stochastic Parallel Gradient Descent control (SPGD) and a Holographic Phase Conjugate Engine that were developed to advance the state of the art AO control. Innovative variations on the Stochastic Parallel Gradient Descent AO and Extended Source (scene-based) AO algorithms hold significant promise for the future of AO.