At the time the first edition of Rock Mechanics and Engineering was being printed, important progress was being made both in theory and practice of rock mechanics. Some new advances were analysed in an ‘Appendix’ to the book, which is now incorporated, with the necessary additions, in the relevant chapters of the second edition. New developments of the new Austrian tunnelling method (NATM) and similar methods caused the important chapter on underground power-stations to be rewritten, and several new chapters to be added.

The problem of bridging the gap between scientific research in rock mechanics and practical engineering has become more acute. Such bridging has recently been achieved in Fluid Transients (Jaeger 1977); it is also vital to applied rock mechanics, as explained in the Preface to the first edition. Many geologists suggest that the rock quality designation (RQD) of Deere is the most reliable parameter for an engineering classification of jointed rock masses. Some geophysicists did not agree and recently introduced their own more complex classification, based on the combination of several parameters describing rock characteristics. Engineers in charge of the construction of large tunnels and underground works were not convinced by these efforts and base their own designs on the rock deformations they expect to occur.

The second edition deals with these problems in several new chapters. There is no better method to deal with them than the close analysis of some case histories.