Some 35 years ago I was somewhat precariously balanced in a drilling derrick aligning a whipstock into a directional hole in North Holland by the Stokenbury method, and no doubt thinking to myself that I was at the very forefront of technology. During the intervening period it has become obvious to many of us that some of the most significant technical advances in the oil business have been made in drilling, and particularly in the fields of offshore and directional drilling. It has also become apparent that the quality of the technical literature describing these advances has not kept pace with that of the advances themselves in many instances. A particular glaring example of this has been in the field of directional drilling where a large literature gap has existed for many years. I am delighted to see this gap now filled with the present volume by my friend Tom Inglis. Indeed it is only after reading his comprehensive book that I realise the extent of my own ignorance of the latest techniques of directional drilling and how desirable it was to have an authoritative text on the subject. I feel sure that this volume will be welcomed by the industry and warmly recommend it to all who are in any way involved and interested in the fascinating world of drilling.