Information on the petroleum geology of the North Sea continues to accrue at an astounding rate, which alone would warrant a fourth edition of this classic work. However, since the publication of the third edition emphasis within the petroleum industry has shifted from exploration to the appraisal and development of existing hydrocarbon resources. This change is reflected in this new edition, which has been significantly expanded to accomodate the additional material. The centrepiece of the book, however, remains a series of descriptions, in stratigraphic order, of the depositional history and