Andrew S. Tanenbaum has a B.S. Degree from M.I.T. and a Ph.D. from the University of California at Berkeley. He is currently a Professor of Computer Science at the Vrije Universiteit in Amsterdam, The Netherlands, where he heads the Computer Systems Group. He is also Dean of the Advanced School for Computing and Imaging, an interuniversity graduate school doing research on advanced parallel, distributed, and imaging systems. Nevertheless, he is trying very hard to avoid turning into a bureaucrat.In the past, he has done research on compilers, operating systems, networking, and local-area distributed systems. His current research focuses primarily on the design of wide-area distributed systems that scale to a billion users. These research projects have led to five books and over 85 referred papers in journals and conference proceedings.Prof. Tanenbaum has also produced a considerable volume of software. He was the principal architect of the Amsterdam Compiler Kit, a widely-used toolkit for writing portable compilers, as well as of MINIX, a small UNIX clone intended for use in student programming labs. Together with his Ph.D. students and programmers, he helped design the Amoeba distributed operating system, a high-performance microkernel-based distributed operating system. The MINIX and Amoeba systems are now available for free via the Internet. Prof. Tanenbaum is a Fellow of the ACM, a Fellow of the IEEE, a member of the Royal Netherlands Academy of Arts and Sciences, winner of the 1994 ACM Karl V. Karlstrom Outstanding Educator Award, and winner of the 1997 ACM/SIGCSE Award for Outstanding Contributions to Computer Science Education. He is also listed in Who's Who in the World. Maarten van Steen is a professor at the Vrije Universiteit, Amsterdam where he teaches operating systems, computer networks, and distributed systems. He has also given various highly successful courses on computer systems related subjects to ICT professionals from industry and governmental organizations. Prof. van Steen studied Applied Mathematics at Twente University and received a Ph.D. from Leiden University in Computer Science. After his graduate studies he went to work for an industrial research laboratory where he eventually became head of a group concentrating on programming support for parallel applications. After five years of struggling to simultaneously do research and management, he decided to return to academia, first as an assistant professor in Computer Science at the Erasmus University Rotterdam, and later as an assistant professor in Andrew Tanenbaum's group at the Vrije Universiteit Amsterdam. His current research concentrates on large-scale distributed systems. Part of his research focusses on Web-based systems, in particular adaptive distribution and replication in (collaborative) content distribution networks. Another subject of extensive research is fully decentralized (gossip based) peer-to-peer systems for wired as well as wireless ad hoc networks.