Dear Colleagues,

The 18th ICFA Beam Dynamics Workshop on Future Light Sources, "Physics of and Science with the X-Ray Free-Electron Laser", will take place in Arcidosso (Italy) on September 10-15, 2000. The Workshop is organized with two main working groups and subgroups. Each working group has a coordinator who will organize the work of the group, including the formation of subgroups. The working group coordinators will give the final summary report on the last day of the workshop. The two main groups are:

• Group I: Physics and technology of the XFEL. Group Coordinator: Alberto Renieri (ENEA)
• Group II: Science with the XFEL. Group Coordinator: Mark Sutton (McGill University).

The workshop will be opened by four introductory talks:

• Present status of the X-ray FEL. Speaker: Kwang-Je Kim (ANL)
• Physics and technology issues for an XFEL. Speaker: Jamie Rosenzweig (UCLA)
• Present status of experiments with short X-ray pulses and/or coherent X-ray pulses. Speaker: Andreas Freund (ESRF)
• What new science can we do with the XFEL? Speaker: Ingolf Lindau (SLAC/Lund U).

Additional talks will be presented during the workshop sessions as plenary talks or talks for groups or subgroups. A room will be available for posters for the full duration of the workshop.

The proceedings of the workshop will be published. We will ask all the participants to send their contributions not later than the last day of October 2000, to have a rapid publication schedule.

Bus transportation to Arcidosso will be provided on September 10 and from Arcidosso on September 16 (see the General Information section for details). Registration and a Welcoming Reception will be held on September 10 in Aldobrandescan Castle from 5-7pm. Housing will be provided at a local hotel, within walking distance from the XII century castle where the Workshop sessions will be held. Lunch and coffee will be provided for the participants at the castle. A companion program with visits to local points of historical and artistic interest will be organized.

We hope to see you in Arcidosso in September 2000.