  A general formula for physical observables in Chern-Simons theory with an
arbitrary compact Lie group $G$, on an arbitrary closed oriented
three-dimensional manifold $\cM$ is derived in terms of vacuum expectation
values of Wilson loops in ${\cal S}^3$. Surgery presentation of $\cM$ and the
Kirby moves are implemented as the main ingredients of the approach. The case
of $G={\rm SU}(n)$ is explicitly calculated.
