The properties of dusty plasmas — low-temperature plasmas containing charged macroparticles — are considered. The most important elementary processes in dusty plasmas and the forces acting on dust particles are investigated. The results of experimental and theoretical investigations of different states of strongly nonideal dusty plasmas — crystal-like, liquid-like, gas-like — are summarized. Waves and oscillations in dusty plasmas, as well as their damping and instability mechanisms, are studied. Some results on dusty plasma investigated under microgravity conditions are presented. New directions of experimental research and potential applications of dusty plasmas are discussed.