The problem of ensuring reliable signal transmission in the presence of interference is currently considered the most important problem in applied information theory. This monograph is a brief introduction to the modern theory of methods for increasing noise immunity. It contains a compact presentation of the latest methods, views and results, allowing you to review the entire problem as a whole. The purpose of the book is to help a beginner to work in this area to get a general idea of ​ ​ the problem and get the basic initial information that will allow you to start studying special literature. The book is designed for radiophysicists and radio engineers.