Metal additive manufacturing (AM) is a production method that has seen increased growth over the last ten years. AM, commonly known as 3D-printing, is the process by which material is built up, layer-by-layer, to produce a 3D object. Many people know about AM through its use with polymeric filament extrusion. Metallic parts made via AM are being used in many industries; among them are the automotive, aerospace, and medical industries. Metal AM encompasses many processes. Each process can be defined by the feedstock material used and the energy source by which the part is created with. Laser sintering, laser melting, electron beam melting, and direct energy deposition are some of the processes used to build metallic parts. As growth continues in the metal AM sector, research is being bolstered. Areas of current research include additional material systems, powder feedstock recycling and microstructural changes during the processing of metals in AM.