This book is written for a wide range of graduate and undergraduate students studying various courses in physics and astronomy. It is accompanied by the award-winning educational Windows(r) software package "Planets and Satellites" developed by the author. This text, together with the interactive software, is intended to help students learn and understand the fundamental concepts and the laws of physics as they apply to the fascinating world of the motions of natural and artificial celestial bodies. The primary aim of the book is the understanding of the foundations of classical and modern physics, while their application to celestial mechanics is used to illustrate these concepts. The simulation programs create vivid and lasting impressions of the investigated phenomena, and provide students and their instructors with a powerful tool that enables them to explore basic concepts that are difficult to study and teach in an abstract conventional manner. Students can read the text and work with the software at a pace that they can enjoy, varying parameters of the simulated systems and repeating the most important and interesting experiments on their own. Each section of the textbook is supplied with questions, exercises, and problems. Using some of the suggested simulation programs, students have an opportunity to perform interesting mini-research projects in physics and astronomy. The experience based on student's own actions results in deeper understanding than the mere reception of someone else's knowledge, as a visual impression is much more intensive and permanent than a heard or read one. The simulation programs, with a wealth of predefined examples, make visible the beauty and aesthetics of the mathematics and of the fundamental laws of physics in their application to the motions of celestial bodie