The chapter discusses the advancements and applications of automatic control systems, highlighting their global interest and relevance beyond engineering. Key developments include improvements in thermionic amplifiers, new types of amplifiers for higher powers, and the exploration of analogies between control systems and physiological, neurological, biological, and economic phenomena. The concept of a "closed sequence of dependence" is introduced as a fundamental principle, explaining how systems can exhibit self-excitation and oscillatory behavior. The chapter also addresses the challenges of achieving accurate control in systems with time-delays, particularly in high-power applications. Additionally, it explores the application of automatic control in chemical industries and the role of manual control in defense and aircraft operations, emphasizing the importance of reducing response delays. The chapter concludes by noting the ongoing research efforts in these areas and the potential for further advancements.The chapter discusses the advancements and applications of automatic control systems, highlighting their global interest and relevance beyond engineering. Key developments include improvements in thermionic amplifiers, new types of amplifiers for higher powers, and the exploration of analogies between control systems and physiological, neurological, biological, and economic phenomena. The concept of a "closed sequence of dependence" is introduced as a fundamental principle, explaining how systems can exhibit self-excitation and oscillatory behavior. The chapter also addresses the challenges of achieving accurate control in systems with time-delays, particularly in high-power applications. Additionally, it explores the application of automatic control in chemical industries and the role of manual control in defense and aircraft operations, emphasizing the importance of reducing response delays. The chapter concludes by noting the ongoing research efforts in these areas and the potential for further advancements.