The modern petroleum refinery is a complex of many highly interrelated processes working to make the petroleum products our nation uses. This paper presents an overview of the operations and processes that are used in today's refineries to produce gasoline, distillates, lube oils, greases, coke, etc. Sufficient background in petroleum properties and chemistry is given to provide a basic understanding of how different refinery processes affect products and their quality. The following processes are described: distillation, catalytic reforming, fluid catalytic cracking, alkylation, coking, hydroprocessing, and isomerization. The many specialized processes used to make lube oils and greases also are examined. Finally, the paper looks at product blending, and how predictable future events are likely to impact on refining.