This book is a valuable contribution to the development of the advanced digital technology in application for gear drives. The book presents a unique approach for solving complex gear design and manufacturing problems. The Volume 1 covers variety of applications of the Direct Digital Simulation method with numerous graphic examples and software samples. The book if targeted on gear engineers, students and advanced gear professionals. The high-resolution 3-dimentional graphic simulations will help the beginners to learn this complicated area of mechanics. The software samples will be useful for every day work of engineers and for advanced gear software developers. With this book the authors are responding to the numerous inquiries for publishing of practical learning materials about the new numerical method for gear development.