  In this paper the current release of the Monte Carlo event generator Sherpa,
version 1.1, is presented. Sherpa is a general-purpose tool for the simulation
of particle collisions at high-energy colliders. It contains a very flexible
tree-level matrix-element generator for the calculation of hard scattering
processes within the Standard Model and various new physics models. The
emission of additional QCD partons off the initial and final states is
described through a parton-shower model. To consistently combine multi-parton
matrix elements with the QCD parton cascades the approach of Catani, Krauss,
Kuhn and Webber is employed. A simple model of multiple interactions is used to
account for underlying events in hadron--hadron collisions. The fragmentation
of partons into primary hadrons is described using a phenomenological
cluster-hadronisation model. A comprehensive library for simulating tau-lepton
and hadron decays is provided. Where available form-factor models and matrix
elements are used, allowing for the inclusion of spin correlations; effects of
virtual and real QED corrections are included using the approach of Yennie,
Frautschi and Suura.
