Modern inertial sensors and systems cover more than five decades of continuous research and development involving various branches of science and engineering. Various technologies have emerged in an evolutionary manner surpassing the earlier ones in performance and reliability. The subject is still growing with proliferation in newer cost effec-tive applications, while its wider usage in aerospace systems continues. This book exposes the readers to the subject of inertial navigation, the inertial sensors and inertial systems in a unified manner while emphasizing the growth areas in emerging technologies such as micro-electromechanical inertial sensors, satellite navigation, satellite navigation integrated inertial navigation, hemispherical resonator gyro, vibrating beam accelerometer, interferometric fibre optic gyro, inertial sensor signal processing, redundant inertial systems and the quite recent emergence of cold atom interferometer based inertial sensors. The contents are imaginatively designed that will of interest to a wide spectrum of readers. The book has been written with utmost lucidity and clarity and explanations provided with a large number of illustrative figures. Besides being an ideal introduction to the principles of inertial sensors and systems for undergraduate and postgraduate students of aerospace engineering, the topics dealt with will also be of benefit to practising engineers and can assist the researchers to locate excellent references for research work. The authors have had three decades of design and application research experience in premier research institutions and have made use of their experience in giving a user-friendly shape to the book.