When the first edition of this book was completed in 1989 the study of earthquakes and faulting was still developing rapidly and has continued to do so in the intervening years. It thus seemed necessary, in order to keep this work useful, that an extensively revised and updated new edition be prepared.

Progress during these dozen years has not, of course, been uniform. There have been rapid developments in some areas whereas others have been relatively static. As a result, some sections and chapters have been extensively revised while others remain almost the same, undergoing only minor updating. A goal in this revision was to retain the same overall length, and this has been largely successful. This necessitated the removal of material which in hindsight no longer seemed as vital as it once did or which had been superseded by more recent results.

The two major themes of the first edition have been further developed in the interim. The first of these is the intimate connection between fault and earthquake mechanics. Fault mechanics in 1989 was still in a primitive state, but rapid progress during the 1990s has brought the discovery of the main fault scaling laws, the nature of fault populations, and how these result from the processes of fault growth and interaction. This new knowledge of fault mechanics provides a fuller appreciation of faulting and earthquakes as two aspects of the same dynamical system: the former its long-timescale and the latter its short-timescale manifestation.