The high-energy physics community in the United States has gathered at intervals since 1982 to examine and articulate the current state of the discipline and to chart its future. This year, the APS Divisions of Particles and Fields and of the Physics of Beams are organizing a Summer Study on the Future of Particle Physics that will consider the field in all its richness and diversity. Snowmass 2001 will consider experiments at the highest energies, experiments of exceptional sensitivity, and experiments that explore very high scales through virtual effects; accelerators to address a broad range of scientific opportunities; accelerator research to provide information for knowledgeable decisions about future projects, and accelerator research and technology development for the long term; theory that develops hand-in-hand with experiment and visionary theory that hasn't yet engaged experimental particle physics directly. The workshop will examine accelerator experiments as well as astroparticle, particle astrophysics, and cosmological studies that use natural sources. It will examine the interplay between particle physics and new technologies, and will explore the interactions between particle physics and related fields.  Snowmass 2001 will be a forum for the critical examination of future projects, and will provide crucial community input to the long-range planning activities undertaken by the science funding agencies and the High Energy Physics Advisory Panel. It will be an ideal place for a broad community of scientists to examine initiatives for new accelerators and new detectors that are being developed throughout the world.  Every member of the high-energy physics community is welcome. We look forward to extensive international participation. For a more detailed description, see the October 31, 2000, Snowmass 2001 Report to the High Energy Physics Advisory Panel