Abstract: The development of scanning tunneling microscopy (STM) and related local probe methods has led to a novel perception of nanometer- and atomic-scale structures and processes. Since the structural information is obtained directly in real space, the scanning probe techniques offer considerable advantages compared with diffraction techniques for the investigation of non-periodic structures at solid surfaces such as point defects, steps, dislocations, and grain boundaries. Moreover, the local probe methods allow one to study almost any kind of physical property of microstructures with submicron down to atomic resolution including electrical, chemical, magnetic, and mechanical properties. ( 34 Refs) Descriptors: crystal microstructure; dislocations; grain boundaries; point defects; scanning tunnelling microscopy; scanning tunnelling spectroscopy; surface structure Identifiers: nanometer scale structures; electrical properties; chemical properties; magnetic properties; scanning probe microscopy; spectroscopy; microstructures; physical properties; scanning tunneling microscopy; STM; atomic-scale structures; real space; solid surfaces; point defects; steps; dislocations; grain boundaries; atomic resolution; mechanical properties Class Codes: A6480G (Microstructure); A6820 (Solid surface structure); A6170B ( Interstitials and vacancies); A6170L (Slip, creep, internal friction and other indirect evidence of dislocations); A6170N (Grain and twin boundaries )