This unique monograph contains a comprehensive overview of celestial mechanics, providing the reader with a solid basis on which to build an understanding of the theory of interplanetary flights. The theoretical development is illustrated with a number of practical examples, bringing to bear the author's wealth of experience gained from working of the Soviet space programme. Many examples are taken from current space topics, including the Shoemaker-Levy 9 comet, the flight of Ulysses over the Solar poles, and the Voyagers' tour of the Solar system. Recent theoretical achivements, such as the intriguing problem of chaos in the Solar system, are also covered. This book will appeal to students and researchers interested in both the theoretical and applied aspects of the topic. The clarity of the exposition renders the subject matter accessible to senior undergraduates and graduate students of mathematics, physics and astrophysics.