  We define quantum exterior product wedge_h and quantum exterior differential
d_h on Poisson manifolds, of which symplectic manifolds are an important class
of examples. Quantum de Rham cohomology is defined as the cohomology of d_h. We
also define quantum Dolbeault cohomology. Quantum hard Lefschetz theorem is
proved. We also define a version of quantum integral, and prove the quantum
Stokes theorem. By the trick of replacing d by d_h and wedge by wedge_h in the
usual definitions, we define many quantum analogues of important objects in
differential geometry, e.g. quantum curvature. The quantum characteristic
classes are then studied along the lines of classical Chern-Weil theory, i.e.,
they can be represented by expressions of quantum curvature. Quantum
equivariant de Rham cohomology is defined in a similar fashion. Calculations
are done for some examples, which show that quantum de Rham cohomology is
different from the quantum cohomology defined using pseudo-holomorphic curves.
