Laws of informatics in the problem of knowledge of complex systems

In the article is stated history of use of information methods in researches of natural and artificial systems. Properties of complex systems are described. Laws of informatics and the basic results received with their use are resulted: preservation of uncertainty (information), the information form of the Heisenberg uncertainty principle, an estimation of volume of the information and number of particles in the Universe, information classification of kinds of a matter, tendencies of change of weight of usual substance at expansion of the Universe. Conditions and estimations of characteristics of cognoscibility of complex systems are given, of the Universe: factor of compression of the information, limiting opportunities of knowledge. Directions of the further researches are certain.