Cutting fluids play a major role in increasing productivity and reducing costs by making possible the use of higher cutting speeds, higher feed rates, and greater depths of cut. After listing the functions of cutting fluids, this article then covers the major types, characteristics, advantages and limitations of cutting and grinding fluids, such as cutting oils, water-miscible fluids, gaseous fluids, pastes, and solid lubricants along with their subtypes. It discusses the factors considered during the selection of cutting fluid, focusing on machinability (or grindability) of the material, compatibility (metallurgical, chemical, and human), and acceptability (fluid properties, reliability, and stability)....