Gas hydrates are of particular interest to those working in the natural gas industry. Thus the main audience for this book are the engineers and scientists who work in this field. Provided in this book are the tools for predicting hydrate formation and details on how to combat them. The genesis of this book was a one-day course presented to engineers who work in the natural gas business. In particular these companies produce, process, and transport natural gas. The book has been expanded from the original set of class notes. Much of the new material came from feedback from attendees. Many people outside the field of natural gas have also attended the course and found some value in the material. These include oceanographers studying the hydrate deposits on the seabeds throughout the world. Astronomers investigating the possibility of hydrates on the planets of the solar system as well as other celestial bodies may also find some of the material in this book of some use. And those who are simply curious about these interesting compounds will find this book to be useful. The structure of the book is a little unusual. The chapters are meant to be approximately independent, however they do follow from the more simple introductory topics to the more advanced applications. Occasionally it is necessary to take a concept in a subsequent chapter in order to make a point in the current chapter. This is unfortunate, but it is also necessary. The purpose of this book is to explain exactly what gas hydrates are, under what conditions they form, and what can be done to combat their formation. Another purpose of this book is to explore some of the myths associated with gas hydrates. The material is organized and presented in such a way that the average engineer can use the information in their day-to-day work. In some sections of the book, especially those dealing with dehydration, pipeline heat loss calculations, and lineheater design, the reader would benefit greatly if they have the ability to calculate the physical properties of natural gas. The topic of the properties of natural gas is not covered in this book.