The Principles of petroleum economics is an exciting, fascinating subject that deals with energy which is very significant of live. And it is one of the most influential player in the world economy, so having a comprehensive understanding of this vital area is key for anyone working within the oil and gas or energy industries. Furthermore, the oil used in all industrials vehicles, power plant system, and even in military applications. This book is written for use as a textbook by undergraduate student course on Principles of petroleum economics to student of International Economic Relations department in Collage of political science, in Al- Nahrain University in Baghdad –Iraq. This book is organized in five topic areas: 1. Chapter 1: The historical of Oil Background. 2. Chapter 2 : The Oil Economic Concepts. 3. Chapter 3 : The kind of the Oil Investment. 4. Chapter 4: The Means of Transportation of oil. 5. Chapter 5: The pricing of oil . I am very thankful to my students and Colleagues who encourage me in writing this book, especially Dr. Ahmad Alhamdani and the Instr. Aula Abdul Ghaffour Mohammad who reviewed the content of this book and gave a valuable advices.