The book starts with optimum drilling practices, which provide the highest rate of penetration (ROP) at minimum footage cost ($/ft). While these factors are commonly acknowledged in the drilling community, they need to be underscored in any drilling text, especially for those entering the science of drilling and production. These fundamental elements of drilling provide the foundation for more detailed analyses throughout the book. Special features of the book are comprehensive presentation of: 1) Drilling hydraulics, 2) Drillstring mechanics including vibration control, 3) Drilling economics, 4) Maintenance and reliability, and 5) Directional drilling including bit navigation, well path monitoring and directional control. Each of these elements are explained through basic engineering mechanics. Discussions are presented with scientific rigor, but in a form easily understood by undergraduate engineering students. This book is suitable as both a university text and as an industry reference guide.