This book is a concise presentation of the science of petroleum. It covers the basic elements of the Petroleum science through eight chapters. The first chapter contains basic definitions together with the chemical composition and physical properties of the petroleum substance. The second chapter is a summary of those geological concepts pertinent to the petroleum habitat rocks. In the following two chapters, petroleum generation, migration, and accumulation into petroleum reservoirs, are described. Petroleum exploration techniques, well drilling, production and storage, are dealt with in the last four chapters. The book is designed to serve audiences from both the academic and industrial worlds. University students and staff members of oil-exploration companies will find this book very helpful in increasing their knowledge and in boasting their application effort's efficiency. I will be grateful for readers who can let me know of any comment of criticism. Such contributions shall be used in improving future book updates. My email address is hamidalsadi@hotmail.com.