The work described in this report has benefited from conversations with and use by a large number of people. We also thank those that have helped in the implementation of MPICH, particularly Patrick Bridges and Edward Karrels. Particular thanks goes to Nathan Doss and Anthony Skjellum for valuable help in the implementation and development of MPICH. Debbie Swider, who worked with the mpich group for several years, helped support and enrich the mpich implementation. More recent extensive contributions have been made by Omer Zaki (for Jumpshot). Anthony Chan has helped with SLOG and Jumpshot-3. David Ashton, who has developed the Windows NT version of mpich and was supported by a grant from the Microsoft corporation, has also contributed to mpich. The C++ bindings have been contributed by Andrew Lumsdaine and Jeff Squyres of Notre Dame. Rajeev Thakur of Argonne is responsible for the ROMIO implementation of the MPI-2 I/O functions. The Globus2 device is due to Nick Karonis of Northern Illinois University and Brian Toonen of Argonne National Laboratory.