An ambitious exercise to encode part of the knowledge in the Encyclopaedia Britannica into a very large knowledge base (VLKB); ‘CYC’ is derived from encyclopedia. Inference procedures are incorporated into the system in order to answer questions and deduce results according to user requirements. In this way, both explicit and implicit knowledge is being captured. The project is based on the premise that a very large baseline of knowledge must be acquired before intelligent behaviour can emerge.