Atomistic modelling of magnetic materials provides unprecedented detail about the
underlying physical processes that govern their macroscopic properties, and allows
the simulation of complex effects such as surface anisotropy, ultrafast laser-induced
spin dynamics, exchange bias, and mi- crostructural effects. Here we present the key
methods used in atomistic spin models which are then applied to a range of magnetic
problems. We detail the parallelisation strategies used which enable the routine simulation
of extended systems with full atomistic resolution.