(ESP) An object-oriented extension of KL0 by Chikayama. ESP has backtracking-based control, unification-based parameter passing and object-oriented calling. An object in ESP is an axiom set. A class definition consists of nature definitions (inheritance), slot definitions (class variables) and clause definitions. ESP has multiple inheritance similar to Flavors. It has been implemented for ICOT's PSI Sequential Inference machine. See also CESP.