The concentration covers major components of the downstream oil & gas industries and their further conversion to petrochemicals. Starting with crude oil treatments and moving through major oil & gas refining processes and their dependence on different feedstock's. Petrochemical building blocks and their derivatives including, basic, intermediate and final products are introduced with emphasis on those produced in Saudi Arabia. Tools for analyzing and evaluating the economical and environmental impacts of the downstream industry is discussed as well as the challenges in the integration of refining and petrochemicals.