This chapter provides an introduction to the existence of ionized gases and plasma in nature and in devices that are in common use and new devices that are being developed. With the exception of our near-Earth environment, ionized gases are common in the universe. The electrical properties of plasma allow utilization in energy transfer and in force applications in unique ways. Plasmas in nature are generally of low pressure and high temperature. Laboratory devices can generate plasmas with low and high pressures and low and high temperatures. Existing devices that utilize plasmas are identified, and some applications that promise future revolutionary developments are discussed.