Contributors. Introduction. Atomic-level geometry of crystalline interfaces D. Wolf. Experimental investigation of internal interfaces in solids D.N. Seidman. Bulk interfaces. Part I: Bulk interfaces. Correlation between the structure and energy of grain boundaries in metals D. Wolf, K.L. Merkle. Grain and interphase boundaries in ceramics and ceramic composites M.G. Norton, C.B. Carter. Special properties of E grain boundaries G. Palumbo, K.T. Aust. Grain boundary structure and migration D.A. Smith. Role of interfaces in melting and solid-state amorphization S.R. Phillpot, S. Yip, P.R. Okamoto, D. Wolf. Wetting of surfaces and grain boundaries D.R. Clarke, M. Gee. Part II: Semi-bulk and thin-film interfaces. Structural, electronic and magnetic properties of thin films and superlattices A. Continenza, C.Li, A.J. Freeman. Surfaces and interfaces as studied by scanning-tunneling microscopy R. Hamers. Epitaxy of semiconductor thin films J. Batstone. Phase behavior of monolayers S.G.J. Mochrie, D. Gibbs, D.M. Zehner. Elastic and structural properties of superlattices M. Grimsditch, I.K. Schuller. Computer simulation of the elastic behavior of interface materials D. Wolf, J. Jasczak. Interfaces within intercalation compounds M.S. Dresselhaus, G. Dresselhaus. Nanophase materials: structure-property correlations R.W. Siegel. Part III: Role of interface chemistry. Interfacial segregation, bonding and reactions C.L. Briant. Physics and chemistry of segregation at internal interfaces R. Kirchheim. Atomic resolution study of solute-atom segregation at grain boundaries: experiments and Monte Carlo simulations S.M. Foiles, D. Seidman. Amorphization by interfacial reaction W.L. Johnson. Relationship between structural and electronic properties of metal-semiconductor interfaces R. Tung. Electronic properties of semiconductor-semiconductor interfaces and their control using interface chemistry D.W. Niles, G. Margaritondo. Microscopic nature of metal-polymer interfaces P.S. Ho, B.D. Silverman, S-L. Chiu. Part IV: Fracture behavior. Tensile strength of interfaces A.S. Argon, V. Gupta. Microstructure and fracture resistance of metal/ceramic interfaces A.G. Evans, M. Ruhle. Role of interface dislocations and surface ledges in the work of adhesion D. Wolf, J. Jaszczak. Microstructural and segregation effects in the fracture of polycrystals D.J. Srolovitz, W. Yang.