Book excerpt: This book covers the fundamentals of reservoir engineering in the recovery of hydrocarbons from underground reservoirs. It provides a comprehensive introduction to the topic, including discussion of recovery processes, material balance, fluid properties and fluid flow. It also contains details of multiphase flow, including pore-scale displacement processes and their impact on relative permeability, with a presentation of analytical solutions to multiphase flow equations. Created specifically to aid students through undergraduate and graduate courses, this book also includes exercises with worked solutions, and examples of previous exam papers for further guidance and practice.As part of the Imperial College Lectures in Petroleum Engineering, and based on a lecture series on the same topic, Reservoir Engineering provides the introductory information needed for students of the earth sciences, petroleum engineering, engineering and geoscience.