The book is devoted to one of the new sections of cybernetics the theory of adaptive systems. Methods of analysis and synthesis of adaptive regulators are studied, ensuring the achievement of the management goal in conditions of little information about the control object and about the properties of external influences. The focus is on approaches that have emerged in recent years and are presented only in the journal literature. The method of recurrent target inequalities, the method of stochastic recurrent estimation and the method of velocity gradient . are considered in detail. The book is intended for engineers, researchers in the field of technical cybernetics and mathematics, teachers and senior students of universities interested in the theory of adaptive systems and its applications.