  Methods are reviewed for computing the instanton expansion of the
prepotential for N=2 Seiberg-Witten theory with non-hyperelliptic curves. These
results, when compared with the instanton expansion obtained from the
microscopic Lagrangian, provide detailed tests of M-theory. Group theoretic
regularities of F_ 1-inst allow one to "reverse engineer" a Seiberg-Witten
curve for SU(N) with two antisymmetric representations and N_f \leq 3
fundamental hypermultiplet representations, a result not yet available by other
methods. Consistency with M-theory requires a curve of infinite order.
