In the present book considered the possibility for direct use of mechanochemical methods for preparation of new nanocrystalline precursors owing to the free-of-rubbing mechanical activation of different systems. The use of very hard milling tools of mechanochemical reactors allows one to offer also a new way of charge preparation with a composition and structure suitable for growing the bulk crystals. Numerous examples are given the possibility of using this new technology for the produce new compounds and nanocrystals. For the first time is presented a review on properties, research methods, producing and application of nanocrystals and composites of silver halides and sulfur by well-know McCormick method - is the mechanosynthesis by using non-purpose water-soluble or volatile reaction product.