The field of engineering which is concerned with hydrocarbon production is known as petroleum engineering. It is multi-disciplinary field that applies the principles of mechanical engineering, chemical engineering, mining engineering and physics. Petroleum engineering is divided into various sub fields such as reservoir engineering, drilling engineering and petrophysics. Its key objective is to extract liquid and gaseous hydrocarbons from the Earth's surface. This requires estimation of recoverable volume and a detailed understanding of water and oil within a porous rock under very high pressures. The processes used in petroleum engineering are divided into upstream, midstream and downstream sectors. The upstream activities involve searching for oil and gas fields which are located underground or underwater. Midstream sector is related to the transportation of oil and gas. The downstream processes focus on refining of crude oil to obtain gasoline. The various sub-fields of petroleum engineering along with technological progress that have future implications are glanced at in this book. The topics covered herein deal with the core subjects of petroleum engineering. This book will serve as a valuable source of reference for those interested in this field.