This paper provides an overview of the research on the use of high-energy mechanical milling in processing advanced materials. The focus is on the major understanding achieved on each of the major topics in this area. This overview demonstrates that high-energy mechanical milling can be used to produce several different types of materials, including amorphous alloy powders, nanocrystalline powders, intermetallic powders, composite and nanocomposite powders, and nanopowders. Good understanding of the mechanisms related to the process for each of these purposes has been achieved at the phenomenological level. However, accurate quantification and modelling of high-energy mechanical milling is still not available, even though several research groups have investigated these topics. The whole area of mathematically describing and modelling the high energy milling process deserves the close attention of all materials scientists and engineers working in the area of processing powder materials using high-energy mechanical milling. Without mastering the art of optimising, controlling and predicting the process, there is no hope of developing this powerful process into a mainstream industrial scale materials processing process as has happened for metallurgical processes, such as melting, casting, or heat treatment. Issues related to the consolidation of the mechanically milled powders and future development in this area of high-energy mechanical milling have also been commented on. (C) 2003 Elsevier Ltd. All rights reserved.