This document discusses magnetohydrodynamics (MHD). It begins by covering Faraday's early experimental work in electromagnetic induction and the theoretical principles of MHD. It then describes different types of MHD systems including open cycle systems using fuel and alkali metals, closed cycle systems using working fluids, and seeded inert gas and liquid metal systems. The document notes advantages of MHD such as high efficiency, lack of moving parts, and potential applications in fusion reactors and cancer treatment.