About the Author: Ricardo Maronna is a Professor in the Department of Mathematics, Faculty of Exact Sciences, National University of La Plata, Argentina, and researcher at C.I.C.P.B.A. He is the author of numerous research articles on robust statistics, especially in the areas of regression and multivariate analysis. Doug Martin is a Professor in the Department of Statistics, and Director of the Computational Finance Program at the University of Washington in Seattle, Washington. He was a consultant at Bell Laboratories for many years, and author of numerous research articles on robust methods for time series. Martin founded the original S-PLUS company Statistical Sciences, Inc., and led the development of the S-PLUS Robust Statistics Library. Victor Yohai, is a Professor in the Department of Mathematics, Faculty of Exact and Natural Sciences, University of Buenos Aires, Argentina, and researcher at CONICET. He is the author of a large number of important research articles on robust statistics, in particular on regression and time series. Several of the procedures proposed by him have been implemented in the robust library of S-PLUS.