This second volume in the new series produced by the Mineralogical Society is concerned with the study of rocks from the deep continental crust. It is, we hope, timely to summarize recent petrological advances contributing to this field of active interest. Based mainly on review papers read at a conference, the chapters have subsequently been revised and expanded, while the editors have produced an introductory overview as Chapter 1. The conference was the Winter Meeting of the Mineralogical Society on 15 December 1988, at wh ich Prof. R. C. Newton delivered the 20th Hallimond Lecture of the Society (which forms the basis of Ch. 7). The editors are grateful to all who contrib uted to the smooth running of the meeting at Kingston Polytechnic, and in the ensuing preparation of the volume: in particular, we sincerely thank all of the following for their labours as referees: A. J. Baker, L. M. Barron, M. J. Bickle, A. D. Chambers, J. D. Clemens, J. S. Daly, G. T. R. Droop, C. R. L. Friend, E. S. Grew, S. L. Harley, R. S. Harmon, N. B. W. Harris, B. Harte, T. J. B. Holland, N. F. C. Hudson, W. S. MacKenzie, W. Perkins, H. R. Rollinson, J. W. Sheraton, D. J. Waters, R. H. Worden and B. W. D. Yardley. John R.