  We present a brief summary of various aspects of the electron-cloud effect
(ECE) in accelerators. For further details, the reader is encouraged to refer
to the proceedings of many prior workshops, either dedicated to EC or with
significant EC contents, including the entire "ECLOUD" series [122]. In
addition, the proceedings of the various flavors of Particle Accelerator
Conferences [23] contain a large number of EC-related publications. The ICFA
Beam Dynamics Newsletter series [24] contains one dedicated issue, and several
occasional articles, on EC. An extensive reference database is the LHC website
on EC [25].
