ADDITIVE manufacturing (AM), also known as 3D printing, refers to a group of technologies that create products through the addition of materials (typically layer by layer) rather than by subtraction (through machining or other types of processing). The history of AM traces back over 30 years to 1983 and the invention of stereolithography. Since then, the technology has evolved to include at least 13 different sub-technologies grouped into seven distinct process types. We hope this report serves as a useful primer for managers seeking to develop a basic understanding of the different technologies and processes that fall under the AM umbrella. Although not exhaustive (as the technologies are constantly evolving), we believe this report offers a thorough survey to facilitate enlightened discussion by companies interested in the AM topic.