This volume is the eighth classified bibliography of organic and organometallic crystal structures prepared by the Crystallographic Data Centre, University Chemical Laboratory, Cambridge, and published jointly with the International Union of Crystallography. The first seven volumes covered the years 1935-1975. The present volume provides references principally to compounds whose struc­ tures were reported in the literature during 1975-1976. A few structures published prior to 1975 and omitted from the previous volumes are also included. This volume incorporates some major changes in methods of preparation, indexing, and literature coverage. These changes are designed to give a later cut-off date for the literature coverage, and to make the main classified listing more accessible to the reader through improved indexing. The major technical change was the use of the FR80 microfilm recorder at the Science Research Council Rutherford Laboratory, instead of the Linotron 505 filmsetter, to prepare the master copy of the book. The change necessitated the development of a new set of prQgrams, a project carried out in collaboration with the Atlas Computing Division of the Rutherford Laboratory. The reader may also notice the use of a new type font, developed by Dr A. V. Hershey and made available by Mrs Carla Messina, Dr N. M. Wolcott and Mr J. Hilsenrath of the USA National Bureau of Standards.