This book is about devices that control, create and regulate weight on bit and methods of operational (automatic) control over drilling using downhole motor as a drillbit drive in the book. It concludes survey results analysis of equipment and technologies that focused on drilling optimization and automatization of directional and horizontal wells deepening. The drill string operation while combination drilling was highlighted briefly. The book represents methods and technique and also results of experimental actual weight on bit evaluation and recommends how to carry out an operational...