This special issue contains 23 papers written by leading engineers and scientists from all over the world.

Papers are organized in the following manner: the first five papers discuss the use of ASTM E04 microscopy test methods used to characterize nonmetallic inclusions (E45) as well as any discrete second phase using stereological procedures (E1245) and scanning electron microscopy (E2142), as well as characterization of non-Gaussian grain size distributions (E1181) with the aim of improving these test methods.

Then there are 11 papers to follow that evaluate microscopy methods and other technologies to characterize a wide range of cast or wrought metals and alloys.

Finally, there are seven papers that present newer, sophisticated technologies for solving the metallurgical problems.

Authors of these papers specialize in the characterization of metals and alloys of many compositions, made by a wide variety of processes, followed by a variety of casting or hot working processes; some of the alloys were further processed by a variety of heat treatment processes, surface hardening techniques and welding procedures. Overall, this special issue encompasses a variety of interesting technologies presented by the world’s foremost engineers and scientists.