Modulated Structure Materials arise in two basic ways. One is through the natural tendency that certain materials have to develoo stable modulations. Tynical examples of this catenory are the lonn oeriod superlattices, the spinodal alloys and other ordered structures. Another way to introduce nodulation into a basic is throuqh our own intervention, that is ~v artificial structure techninues. Such examples as the conposition nodulated films and the seniconductor superlattices have recently received apnreciable attention not only for their noble and unusual nrooerties but also for their...