  We describe a simple method for determining the strong-coupling BPS spectrum
of four dimensional N=2 supersymmetric Yang-Mills theory. The idea is to
represent the magnetic monopoles and dyons in terms of D-brane boundary states
of a non-compact d=2 N=2 Landau-Ginzburg model. In this way the quantum
truncated BPS spectrum at the origin of the moduli space can be directly mapped
to the finite number of primary fields of the superconformal minimal models.
