ENRIQUE CASTILLO, PhD, is a Professor of Applied Mathematics at the University of Cantabria in Santander, Spain. He is a mathematician and a civil engineer and member of the Spanish Royal Academy of Engineering.

ALI S. HADI, PhD, is a Professor of Mathematical, Statistical, and Computational Sciences at the American University in Cairo, Egypt. He is a Stephen H. Weiss Presidential Fellow and Professor Emeritus at Cornell University.

N. BALAKRISHNAN, PhD, is a Professor in the Department of Mathematics and Statistics at McMaster University in Ontario, Canada. He is a Fellow of the American Statistical Association and currently the Editor-in-Chief of Communications in Statistics and Wiley's Encyclopedia of Statistical Sciences, Second Edition.

JOSÉ M. SARABIA, PhD, is a Professor of Statistics in the Department of Economics at the University of Cantabria, Spain. He is a member of the American Statistical Association and is Associate Editor of the journal Test.