This introductory chapter first defines the metal casting process, and then highlights the advantages, importance of foundries, and industrial applications of cast products, with the aid of a labeled sketch and a table. The basic requirements and principal steps in the metal casting process have been explained with the aid of a flow chart; here, safety, environmental aspects, and quality control (QC), in foundry practice, have been taken into consideration. The classification of various metal casting processes has been presented with the aid of a comprehensive classification chart that includes almost all sub-categories of expendable-mold, permanent-mold, and non-traditional casting processes. Chill casting and continuous casting processes have also been illustrated with the aid of labeled sketches. Finally, directional solidification (DS) casting technology, for manufacturing superalloy single-crystal turbine-blades, has been described, which also includes recent developments in the casting technology. This chapter contains 7 diagrams and 6 MCQs with their answers given at the end of the book.