The book reveals the content of subsidiary systems and technologies. The basics of subsidiarity as a natural evolutionary process and patterns in nature and society are described. The diversity of complex systems and the place of subsidiary systems among complex systems are described. A description of separability in the information field as a principle for the emergence of subsidiarity is given. The book describes the factors of subsidiarity. Mechanisms of clustering are described as factors that lead to subsidiarity. Models of subsidiarity are described. The book reveals the relationship between the logic of development and evolution and subsidiarity. Recommendations are given for the application of subsidiarity systems. The book is intended for specialists in management, evolution and intelligent systems.