Emulsions and microemulsions are both stable dispersions of oil-in-water or water-in-oil. Surfactants are the principal agents that enable oil and water to mix. Emulsions are stable dispersions of immiscible liquids, but they are not thermodynamically stable. We say that they are kinetically stable. These type of dispersions are sometimes called macroemulsions. Microemulsions, on the other hand, are thermodynamically stable. While some people insist that microemulsions must be transparent, that is not really a critical part of their description. In the short course we will give a systematic introduction to the mechanisms of kinetic stabilization of macroemulsions, show how macroemulsions are related to microemulsions, and show how to systematically select a surfactant system to make a stable emulsion or microemulsion.