Facilities for using the FEL as a research tool

In this decade the FEL will be used as a tool for serious scientific research. Facilities which will exploit the unique capabilities of FELs are beginning to appear. Among the many issues which these facilities must address regarding the optical beam delivered to users are: stability (position, power, wavelength), quality (transverse mode, spectral purity), flexibility of micropulse and macropulse structure, ease of user control of operating parameters, and complementary experimental facilities. These issues will be explored in the context of some operating and some planned FEL facilities.