Abstract: This paper provides a brief overview of electric propulsion systems and their working. Novel systems and designs for electric propulsion is classified as electrothermal, electrostatic, electromagnetic and even hybrid systems which can be two or more types combined. The various types described here include DC heated Resistojets, Arcjets, Field emission electric propulsion thrusters, magneto-plasma dynamic thrusters, Hall Effect thruster, Colloid and Electrospray thrusters, High efficiency multistage plasma thruster, Pulsed plasma thruster, Electrode-less thrusters, VASIMR, and the gridded and radio frequency ion engines. Each thruster system can be used on the basis of the mission characteristics and determining factors may include cargo weight, thrust required, power budgets, simplicity etcetera. Choice of propellant can also be varied according availability. This paper hopes to provide a basic knowledge of these systems and their properties.