Knowledge base is an organized body of knowledge relating to some domain. Knowledge is a result of reality cognition proved in practice. In other words, knowledge is truths, facts, principles and other knowledge objects accumulated by mankind. Therefore, unlike a database, a knowledge base contains knowable data available in documents, books, articles, reports.

Knowledge base is a semantic model that describes domain and enables to answer to such questions from this domain, answers to which are explicitly absent in the base. Knowledge base is the main component of intelligence and expert systems.

Knowledge objects that form knowledge body are placed in knowledge base, according to a classification methodology adopted in it. Any object includes a set of knowledge elements. Thanks to conceptual relations provided by hypermedia, knowledge elements combine, forming a knowledge base.

1. Information is classified according to the list of headings.
2. Topic (heading) comes out in the article.
3. In the article, there is a term unknown or to be specified, which has a linkage to the thesaurus that contains interpretation of this term.
4. In the article, there is also information (thesis), which has a linkage to relevant information (bibliographical index, document, website).
5. All documents in knowledge base are related.

There are four types of such relations:

1. Commonness is relation between two elements, based on contents of their characteristics.
2. Partitiveness implies relation of whole and its parts.
3. Opposition is found in elements, which have positive and negative characteristics.
4. Interrelation represents interdependence of elements.

Hypermedia is a technique for representation of any information in the form of relatively small blocks, which are associatively interconnected. Hypermedia is a model for interaction of data blocks by association – set of different features, characteristics, parameters. These blocks are texts, images, video films, files, programs, sound fragments. In hypermedia, information is divided into relatively small blocks represented by graph vertices.

While handling hypermedia, user navigates and passes from one vertex to another, moving in knowledge network. Hypermedia can also be browsed through, not referring to the contents of information blocks. Its software runs passages through edges, and forms required documents. The important feature of hypermedia is information space represented by it. Listing of information blocks and establishment of linkages between them depend on developers that determine hypermedia. As a result, special knowledge bases appear. Some of them are supplemented with a routing plan, according to which passages from one block to another are made. In a number of bases, users are permitted to add new information blocks and linkages.

Hypermedia is widely used in learning systems and distance learning. If information blocks of hypermedia mainly consist of texts, it is called hypertext. Nevertheless, it is necessary to keep in mind that text files are used in hypertext, and image or sound files in hypermedia. Thanks to that, in hypermedia it is possible to link to images and sound as well as to their details.