Additive manufacturing (AM) is a set of manufacturing processes that are capable of producing complex parts directly from a computer model of the part. This review provides a history of the early antecedents of these processes. In addition, the different classes of AM processes and their commercialization are presented and discussed along with their fields of use. This paper emphasizes AM processes that produce production quality parts. The review also addresses design issues and the commercial state of the art for production of polymer, metal, and ceramic parts. A main emphasis of this paper is the development and motivations for AM especially during its nascent years. The paper is written for the general readership of manufacturing professionals and researchers.