AbstractA key point in the design and implementation of intelligent systems is the process of building knowledge bases. As most research in the field of artificial intelligence has moved from building general-purpose problem solvers to building knowledge-based systems that address problems limited to a particular domain, many techniques have been proposed for acquisition and representation of the knowledge bases. This article presents an overview of these techniques and describes several aspects related to building knowledge bases and how these can influence the overall implementation of intelligent systems. IntroductionBefore presenting the techniques and features of building knowledge bases, it is necessary to establish the basis for this by first defining knowledge and how it differs from data and information. To clearly distinguish these concepts, it is possible to think of them as part of a hierarchy in which data is the base of the pyramid, followed by information, knowledge and wisdom at the top (Tuthill, 1990). Data consists of raw facts that have no useful meaning or little application until they are correlated and processed to generate what we call information. For example, a file may store a sequence of names and dates (data) that have no meaning until they are tied to company X and represent X's employees (information). Furthermore, stored data becomes information when it can be processed to generate meaningful output for a community of users. When information is synthesized it is called knowledge and is considered at a higher level in the hierarchy just described. In other words, knowledge is a collection of facts, relationships and behaviors of objects in a model represented... at the center of the article... the bibliography. Bibliography Feigenbaum, EA paper presented at the Fifth International Joint Conference on Artificial Intelligence, Los Angeles, California. 1985.Feigenbaum, E, A. The Fifth Generation: Artificial Intelligence and Japan's Computing Challenge to the World. 1983. Reading, Mass: Addison-Wesley.Ginsberg, Matt. Essentials of artificial intelligence. 1993. Morgan Kaufmann Publishers, Inc. Nii, H. Penny. Tools for creating expert systems: definitions. 1993. http://itri.loyola.edu/kb/c3_s2.htm.Patterson, Dan W. Introduction to Artificial Intelligence and Expert Systems. 1990. Prentice-hall, Inc. Tuthil, G. Steven. Knowledge Engineering: Concepts and Practices for Knowledge-Based Systems.1990. Tab Books Inc. Wolfgram, Deborah D. and Dear, Teresa J. and Galbraith, Craig S. Expert Systems for the Technical Professional. 1987. John Wiley & Sons.