Brian Everitt , now retired, was most recently Professor of Statistics in Behavioural Science and Head of the Department of Biostatistics and Computing at the Institute of Psychiatry, King’s College, London, UK. He is joint editor (with Dr. G. Dunn and Professor T. Holford) of the journal Statistical Methods in Medical Research and a Section Editor of the Encyclopedia of Biostatistics published in 1998 by Wiley. His academic interests include multivariate analysis, in particular cluster analysis, the analysis of longitudinal data and graphical techniques.

David Howell is Emeritus Professor of Psychology, University of Vermont, Burlington, VT, USA.  His primary interests are in the field of statistics and experimental methods. Although retired since 2002 he continues to publish in the area of statistical methods. The 5th edition of Fundamental Statistics for the Behavioral Sciences (Duxbury Press) published in 2004 and a new book on categorical data analysis is in preparation.