  Monte Carlo event generators (MCEGs) are the indispensable workhorses of
particle physics, bridging the gap between theoretical ideas and
first-principles calculations on the one hand, and the complex detector
signatures and data of the experimental community on the other hand. All
collider physics experiments are dependent on simulated events by MCEG codes
such as Herwig, Pythia, Sherpa, POWHEG, and MG5_aMC@NLO to design and tune
their detectors and analysis strategies. The development of MCEGs is
overwhelmingly driven by a vibrant community of academics at European
Universities, who also train the next generations of particle phenomenologists.
The new challenges posed by possible future collider-based experiments and the
fact that the first analyses at Run II of the LHC are now frequently limited by
theory uncertainties urge the community to invest into further theoretical and
technical improvements of these essential tools. In this short contribution to
the European Strategy Update, we briefly review the state of the art, and the
further developments that will be needed to meet the challenges of the next
generation.
