Firstly I would like to thank the many authors who have, unwittingly, provided the basis of a large number of the definitions included in this dictionary through their books and papers. Next thanks are due to many members of the ‘allstat’ mailinglist who helped with references to particular terms. I am also extremely grateful to my colleagues, Dr Sophia Rabe-Hesketh and Dr Sabine Landau, for their careful reading of the text and their numerous helpful suggestions. Lastly I have to thank my secretary, Mrs Harriet Meteyard, for maintainingand typingthe many files that contained the material for the dictionary and for her constant reassurance that nothingwas lost!