This chapter provides an overview of magnetorheological finishing (MRF), a precision polishing technology that utilizes magnetically controlled fluid to remove material from complex surfaces. The historical development of MRF is traced, starting from its inception to its widespread application in industries such as optics and semiconductor manufacturing. The chapter discusses the material removal mechanisms involved, including the role of shear stress, magnetic field-induced rheological changes, and chemical reactions. It also explores the selection of magnetorheological fluid components, focusing on the choice of carbonyl iron powder, carrier fluids, and abrasives to optimize performance. The design and operation of MRF equipment, including machine systems and surface figuring processes, are examined. In conclusion, current challenges such as scalability and thermal management are identified, along with future research directions. This chapter serves as a comprehensive guide for understanding MRF technology and its potential for ultra-precision manufacturing applications.