Summary form only given, as follows. A hybrid electrooptical rule-based system (EORBS) is proposed for the fast and parallel implementation of rule-based systems (RBSs). The EORBS is a hybrid system in which electronics is used for the user interface and optics for the inference engine. The EORBS utilizes two-dimensional optical planes as basic computational entities, and is therefore able to provide concurrent inferencing. Unlike conventional RBSs, EORBS provides parallel matching selection and rule-firing. The theoretical performance of EORBS is estimated and is shown to be superior to that of pure electronic RBSs.