Cold spray is a process technology that, for the first time, enables the rapid deposition of a wide range of metals and some other materials in the solid state at temperatures far below their melting points. This chapter provides an overview of the processes involved in cold spray process technologies, namely high-pressure cold spray (HPCS) and low-pressure cold spray (LPCS), explaining differences of LPCS from HPCS. It summarizes the historical background of the cold spray process. The growing international interest in the cold spray process from the early 2000s is also reviewed.