A brief survey of the emerging field termed "Control of Chaos" is given based on about 200 publications in peer reviewed journals. Three major branches of research are discussed in detail: "nonfeedback control" (based on periodic excitation of the system); "OGY method" (based on linearization of Poincaré map) and "Pyragas method" (based on a time-delay feedback). Some unsolved problems concerning the justification of chaos control methods are presented.