Abstract
The FCC-ee is a next generation circular collider proposed for the
post-LHC era at CERN. Its principal motivation is to study the
properties of the Higgs boson; however, it would also have the
capability of operating at very high luminosity on, and around, the
Z pole, and would allow a data sample to be collected five orders of
magnitude larger than that accumulated at LEP. I shall present the
exciting and powerful physics case for such a programme, with
emphasis on the improvements in systematic control with respect to
LEP that are required to exploit fully this huge data set. It is
concluded that the ability of the FCC-ee to operate as a Z factory
adds enormous value to the physics potential of the FCC project.