Much of the material on which this book is based was drawn from the publications of the Society of Petroleum Engineers (SPE). Tribute is due to the SPE and the petroleum engineers, scientists, and authors who have made numerous and significant contributions to the field of reser- voir engineering. This book reflects my style of teaching during my tenure at Montana Tech of the University of Montana and my under- standing of the subject of reservoir engineering. I would like to thank all my former students at Montana Tech for putting up with me and my Egyptian temper; it was fun. I am sure they will remember that I did my best to teach them reservoir engineering and my sincere desire to help them with their careers.