The field of application of composites is ever-growing because of their unrivalled combinations of functional and structural properties. Such associations seem the more improvable as there are at once manifold possibilities to modify the architecture of composites, their route of elaboration, an ever-increasing scientific potency for both experimental investigations and modelling, and always more demanding materials performances in projects. This presentation wants to illustrate all these aspects by the example of metal matrix composites (MMCs) mostly elaborated by severe plastic deformation. Emphasis is given to results dealing with the effects of composite design and conditions of metalworking on the success of the fabrication process that depends on the uniformity of deformation and/or on the quality of the interfaces. At last, the consequences of all these data, and the need of complementary work, for the continuous improvement of the properties MMCs are delineated.