This monograph provides systematic description of dispersed and compact nanocrystalline metallic and ceramic materials beginning with methods of production and ending with microstructure and properties. The basic methods for producing isolated nanoparticles and nanoclusters, ultradispersed powders and compact nanocrystalline materials are considered. It was described for the first time how atomic and vacancy ordering was employed to create nanostructure in transition metal carbides. Experimental findings regarding the effect of nanocrystalline state on microstructure and mechanical, thermalphysic, optical, magnetic properties of metals, alloys and solid-phase compounds are generalized. Dimensional effects in isolated nanoparticles and compact nanocrystalline materials are discussed in detail. Special attention is given to the role of interfaces in the formation of the structure and properties of compact nanomaterials. The basic model concepts are considered which explain structural peculiarities and anomalous properties of matter in nanocrystalline state. The book will be interesting for specialists dealing with solid state physics, physical chemistry, solid state chemistry and material science, as well as for students and postgraduates of these specialities. Figures 60. Tables 5. References 742.