This investigation into the compositions of Minoan and Mycenaean pottery fabrics was carried out in Oxford at the Research Laboratory for Archaeology and the History of Art by permission of the Director, Dr. E. T. Hall. Mrs. E. E. Richards, co-author of this report, was in charge of the investigation, latterly with the assistance of Mrs. A. Millett. The potential importance of the work undertaken was first suggested by Mr. M. S. F. Hood, then Director of the British School at Athens. Mr. Hood has maintained lively interest in the investigation, and has made many valuable suggestions about the course it should take, as well as providing much of the sherd material. In this connexion we are greatly indebted to Dr. J. Papadimitriou, Director-General of Antiquities in Greece, for granting the necessary export permits. We are also grateful to Mr. M. R. Popham, for scraping selected sherds in the Herakleion Museum and in the Stratigraphical Museum at Knossos, and to Dr. N. Platon, then Ephor of Antiquities in Crete, for allowing this to be done. Sherds from Thebes in the University Museum, Reading, were loaned by Mrs. A. N. Ure; the Rev. Dr. A. J. Arkell provided a set of Mycenaean sherds from Tell el Amarna from the collections in University College, London. Fragments from Rhodes were given by the Department of Greek and Roman Antiquities in the British Museum through the kindness of Mr. D. E. L. Haynes and Mr. R. A. Higgins. Other sherds were provided from the reserve collection in the Ashmolean Museum. The sherds tested in the course of the investigation are now housed in the Ashmolean, with the exception of the group from Thebes (Reading).