The realization of high energy densities in permanent magnetic materials requires careful control of both the composition and the processing conditions to develop appropriate microstructures. In this paper, we will show that manipulation of multiple alloying additions leads to the synthesis of magnetically optimum nanoscale metal matrix composite microstructures in a 9-element modified Nd-Fe-B alloy. The development of composite microstructures in hard magnetic materials is a novel concept resulting in many beneficial effects on the resulting structure/processing/property relationships.