Control is an interdisciplinary branch of engineering and mathematics dealing with the design, identification and analysis to provide specific tasks system desired performance. In the earlier time, system control mainly focused on automatic regulation used in industrial control based on the concept of feedback. Based on transfer function, classical control theory has been later been developed for single-input-single-output and linear time-invariant systems. With the rapid advancements in applied mathematics and computer science, control theory entered the modern control era in 1970's to handle multi-input-multi-output and time-varying systems with high performance and precision. In the last decade, control continues to advance rapidly to intelligent control, distributed control, etc. when new understandings and new technologies emerge.<br><br>Nowadays, control engineering is using control theories and advanced technologies to develop more sophisticated and reliable controllers with a wide range of applications from the flight and propulsion systems of commercial airliners, to the cruise control present in many modern automobiles, to tele-operations, and to real-time internet-based distributed control. It has permeated into every single part of our lives and will continues to play an important role in our societies.