Book excerpt: Introduction to Petroleum Economics is about the process of gathering project data, calculating whether a project should proceed and delivering recommendations. It discusses the science of petroleum economics, starting from square-one, the tools of the trade that petroleum economists use, day in and day out, and also its application. Along the way the author relates some helpful and informative anecdotes based on his almost twenty-year career as a petroleum economist. Vital for all oil professionals as well as students, Introduction to Petroleum Economics unravels the decision-making behind why a petroleum project moves ahead or ends