This Handbook describes and discusses the features that make up the petroleum refining industry. It begins with a description of the crude oils and their nature. It continues with the saleable products from the refining processes, with a review of the modern day environmental impact. There is a complete overview of the processes that make up the refinery with a brief history of the processes. It also describes design technique, operation, and, in the case of catalytic units, the chemistry of the reaction routes. These discussions are supported by calculation procedures and examples, sufficient to enable good input to modern computer simulation packages. The Handbook also covers off-sites and utilities, as well as environmental and safety aspects relevant to the industry.