This is the proceedings of the fourth school in a series of
specialized courses organized by CERN's CAS and the American
USPAS. It deals with intensity limitations. The contribution
thoroughly edited for this publication fall into the
following categories: self and environmental fields -
coherent instabilities and their simulation - beam-beam
interaction - other multi-particle effects - beam source
limitations - engineering limitations.
This exposition of the inner working of high-intensity
particle beams addresses particle physicistsas well as
those that commission new machines. The lecturers were
chosenas being at the forefront of latest developments in
this field.