Book excerpt: Oxide surface materials are widely used in many applications, in particular where chemically modified oxide surfaces are involved. Indeed, in disciplines such as separation, catalysis, bioengineering, electronics, ceramics, etc., modified oxide surfaces are very important. In all cases, the knowledge of their chemical and surface characteristics is of great importance for the understanding and eventual improvement of their performances. This book reviews the latest techniques and procedures in the characterization and chemical modification of the silica surface, presenting a unified and state-of-the-art approach to the relevant analysis techniques and modification procedures, covering 1000 references integrated into one clear concept.