SummaryA key point in the design and implementation of intelligent systems is the process of creating knowledge bases. While most research in the field of AI has moved from building general-purpose problem-solving solutions to building knowledge-based systems that address problems restricted to a particular domain, many techniques have been proposed for the acquisition and representation of knowledge bases. This article presents an overview of these techniques and describes several aspects related to knowledge base construction and how they can affect the overall implementation of intelligent systems. IntroductionBefore the presentation of the techniques and characteristics of knowledge base construction, it is necessary to establish the basis for this by first defining knowledge and how it differs from data and information. In order to clearly distinguish these concepts, they can be considered as part of a hierarchy where data constitutes 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 interconnected 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 relate to company X and represent X's employees (information). Additionally, stored data becomes information when it can be processed to generate a meaningful result for a community of users. When information is synthesized, it is called knowledge and it is considered at a higher level in the hierarchy we have just described. In other words, knowledge is a set of facts, relationships and behaviors of objects in a represented model...... middle of article ......the bibliography.BibliographyFeigenbaum, EA Article 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. The 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 technical professionals. 1987. John Wiley and Sons.