  Perturbing usual type B topological matter with vector $(0,1)$-forms we find
a topological theory which contains explicitly Kodaira-Spencer deformation
theory. It is shown that, in genus zero, three-point correlation functions give
the Yukawa couplings for a generic point in the moduli space of complex
structures. This generalization of type B topological matter seems to be the
correct framework to understand mirror symmetry in terms of two-dimensional
topological field theories.
