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, which ensure achievement of the control goal in conditions of low information about the control object and the properties of external influences. The focus is on approaches that have arisen 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, scientists in the field of technical cybernetics and mathematics, teachers and senior students of universities interested in the theory of adaptive systems and its applications.