Modern aircraft are totally dependent on the installed avionic systems for their economic and effective operation in all weather conditions with a minimum crew. Avionics now count for a third of more of the total cost of the aircraft and employ the most advanced technologies available. This text aims to explain the basic principles and underlying theory of modern avionic systems and how they are implemented with contemporary technology for both civil and military aircraft. The key avionic systems and subjects covered in this book comprise displays and man machine interaction, aerodynamics and flight control, fly-by-wire flight control, inertial sensors and attitude derivation, navigation, air data, autopilots and flight management. Avionic systems integration is discussed and a brief overview is also provided of unmanned aircraft. All systems are explained so that their design and performance can be understood and analysed. Worked examples are included to illustrate the application of the theory and principles covered. The latest developments and directions of research for future systems are included.