The activity of a living cell can be portrayed as a network of interactions involving proteins and nucleic acids that transfer biological information. Intervention in cellular processes requires thorough understanding of the interactions between the molecules, which can be provided by docking techniques. Docking methods attempt to predict the structures of complexes given the structures of the component molecules. We focus hereby on protein-protein docking procedures that employ grid representations of the molecules, and use correlation for searching the solution space and evaluating putative complexes. Geometric surface complementarity is the dominant descriptor in docking. Inclusion of electrostatics often improves the results of geometric docking for soluble proteins, whereas hydrophobic complementarity is more important in construction of oligomers. Using binding-site information in the scan or as a filter helps to identify and up-rank nearly correct solutions. To cite this article: M. Eisenstein, E. Katchalski-Katzir, C. R. Biologies 327 (2004).