Event generators today are indispensable as tools for the
modelling of complex physics processes, that jointly lead to
the production of hundreds of particles per event at LHC
energies. Generators are used to set detector requirements,
to formulate analysis strategies, or to calculate acceptance
corrections.
These lectures describe the physics that goes into the
construction of an event generator, such as hard processes,
initial- and final-state radiation, multiple interactions
and beam remnants, hadronization and decays, and how these
pieces come together. The current main generators are
introduced, and are used to illustrate uncertainties in
the physics modelling. Some trends for the future are
outlined.
