We elaborate on our previous work on N=2 supersymmetric Yang-Mills theory. In
particular, we show how to explicitly determine the low energy quantum
effective action for G=SU(3) from the underlying hyperelliptic Riemann
surface, and calculate the leading instanton corrections. This is done by
solving Picard-Fuchs equations and asymptotically evaluating period integrals.
We find that the dynamics of the SU(3) theory is governed by an Appell system
of type F4, and compute the exact quantum gauge coupling explicitly in terms
of Appell functions.Comment: 57p, harvmac with hyperlinks, 9 uuencoded ps figure