A book aiming to describe all phases of oil and gas pipeline design, construction, and operation can only highlight the skills, equipment, and technology required. Pipeline systems in scores of countries around the world differ in purpose, size, complexity, operating environment, regulatory requirements, economic conditions, and design philosophy. Some aspects of pipeline design and operation are based on physical laws. The relationship between pipeline operating pressure and fluid capacity, for instance, is not affected by political boundaries. Describing such relationships is relatively straightforward. But how each company chooses to control its pipeline, or regulations governing operation and construction often can be introduced only by discussing representative situations in a book of this type.