  Actual calculations of monopole and dyon spectra have previously been
performed in N=4 SYM and in N=2 SYM with gauge group SU(2), and are in total
agreement with duality conjectures for the finite theories. These calculations
are extended to N=2 SYM with higher rank gauge groups, and it turns out that
the SU(2) model with four fundamental hypermultiplet is an exception in that
its soliton spectrum supports duality. This may be an indication that the other
perturbatively finite N=2 theories have non-perturbative contributions to the
beta-function. This talk contains a short summary of recent results.

High Energy Physics - Theory