A short review of the status of electric propulsion (EP) is presented to serve as an introduction to the more specialized technical papers also appearing in this Special Issue (Journal of Propulsion and Power, Vol. 14, No. 5, Sept. –Oct. 1998). The principles of operation and the several types of thrusters that are either operational or in advanced development are discussed Ž rst, followed by some considerations on the necessary power sources. A few prototypical missions are then described to highlight the operational peculiarities of EP, including spacecraft interactions. We conclude with a historical summary of the accumulated  ight experience using this technology.