Many of the observed electronic properties of condensed matter systems such as clusters of atoms, solids with long or short range order (amorphous and liquid metals) are governed by the local atomic arrangements around the probe site. The topics in this important volume include: Molecules and clusters; Point defects and defect complexes in solids; Hydrogen and positive muons in metals and semiconductors; Disordered solids and liquid metals; Diffusion and clustering in bulk, on surfaces; and other restricted geometry; High temperature superconductors including C60 assembled materials.