The proposed book will provide a detailed, technical introduction to the analysis of orbital motion in strongly perturbed environments, focusing on motion about small Solar System bodies, such as comets and asteroids. The author shows why such small bodies are of interest and why they can be used as a motivation for the general analysis of orbital mechanics. He shows how it is possible to model the small body environment, including specialised cases such as those of binary asteroids, comets and 'rubble piles', and how the fundamental equations of motion are derived. The properties of the various solutions to the equations of motion are described and the methods of analysis and their application are discussed. Both ballistic motion and powered motion on and about small bodies are considered and case studies for different small body missions are presented. The author concludes his comprehensive treatment with a discussion of the mechanics of multi-body small body systems and a review of advanced topics and future applications.