TOPSPIN - A Monte Carlo generator for ttbar events with anomalous g-t-tbar couplings.

This note describes a Monte Carlo implementation of the process gg -> ttbar with subsequent leptonic decay of at least one of the t or tbar. A lowest order effective CP violating interaction is introduced in the g-t-tbar vertex. Complete matrix elements are used such that the CP violation can be mediated by the ttbar spin correlation and detected in the final state decay products. The widths of the resonances are included. The hard process generator includes an interface to PYTHIA 6.1 for fragmentation and treatment of the two color flows.