We describe the structure of a magnetic vortex, a magnetic anti-vortex, and
assemblies of these topological objects, which are stable or metastable
structures found in small ferromagnetic systems. These structures and the
related dynamics are well-described by the Landau-Lifshitz-Gilbert equation,
which is a local torque equation that includes dipolar and ferromagnetic
interactions.  Simulations and solutions of linearized versions of this
equation are employed to study these structures and their spin waves and
core dynamics.  Direct comparisons are made with magnetic force microscopy
and magneto-optical Kerr effect experiments on some of the same systems.