  We incorporate both BRS symmetry and anti-BRS symmetry into the quantisation
of topological Yang--Mills theory. This refines previous treatments which
consider only the BRS symmetry. Our formalism brings out very clearly the
geometrical meaning of topological Yang--Mills theory in terms of connections
and curvatures in an enlarged superspace; and its simple relationship to the
geometry of ordinary Yang--Mills theory. We also discover a certain SU(3)
triality between physical spacetime, and the two ghost directions of
superspace. Finally, we demonstrate how to recover the usual gauge-fixed
topological Yang--Mills action from our formalism.
