The first edition of this book was received more kindly than it deserved by some, and with some scepticism by others. It set out to present a simple, concise and reasonably comprehensive introduction to some of the theoretical and empirical criteria which may be used to define rock as a structural material. The objectives - reinforced by the change in title - remain the same, but the approach has been changed considerably and only one or two sections have been retained from the first edition. The particular aim in this edition is to provide a description of the mechanical behaviour of rocks,...