Dr. Angelo Mascarenhas, Senior Scientist at Center for Basic Sciences, NREL (National Renewable Energy Laboratory, USA). One of the pioneers in the area of spontaneous ordering, phase separation, and spontaneous composition modulation in semiconductor alloys. His judgement is not only authoritative, but one that understands the relative importance of spontaneous modulation within "the greater picture" of semiconductor alloys generally. The contributors are all authorities in their respective branches.