This paper briefly reviews state-of-the-art adaptive control systems. It includes a general introduction, followed by the fundamental motivations behind the inception of adaptive controls as well as their historical time-line. We also present several types of adaptive control strategies that have been broadly investigated. Furthermore, we elaborate cutting-edge technological developments in adaptive controls and also discuss their pros and cons. We hope that this review paper can be useful to help researchers and practitioners to identify potential research problems and solutions as well as benefits and limitations associated with each technique.