Subvolume A of two subvolumes on Diffusion in Semiconductors and Non-Metallic Solids consists of a comprehensive and critical compilation of data for the following materials and diffusion in silicon, germanium and their alloys, diffusion in compound semiconductors, diffusion in silicides, chemical diffusion in bulk inhomogeneous semiconductors, grain-boundary and dislocation diffusion in semiconductors and silicides and surface diffusion on semiconductors. Although most of the silicides are not semiconducting, this chapter is included here because a number of them have become integrated in the Si technology and because they were not covered in the previous volume III/26 on diffusion in metallic substances. Subvolume A contains a CD-ROM.