"In this dissertation we have introduced and explained the process of classification of non-textual information. In the introduction part we have explained basic components of the Internet and information retrieval as a whole. We listed particular problems concerning nontextual information retrieval and their possible solutions including examples of certain image and music search engines capable of reverse information retrieval.As a problem, we explained imperfect and unclear demands of a Internet user when creating a query and how that affects the success rate of searche engines.!