This handbook has been compiled for readers with an interest in the oil and gas industry. It is an overview of the main processes and equipment. When we searched for a suitable introduction to be used for new engineers, I discovered that much of the equipment is described in standards, equipment manuals and project documentation. Little material was found to quickly give the reader an overview of the entire oil and gas industry, while still preserving enough detail to let the engineer have an appreciation of the main characteristics and design issues. I have had many requests that downstream processes be included, and have restructured the book into Upstream, Midstream, Refining and Petrochemical, adding basic information on these facilities. The main focus of the book is still the upstream production process. This book is by no means a complete description on the detailed design of any part of this process, and many details have been omitted in order to summarize a vast subject.