  The A_{N - 1} (2, 0) superconformal theory has an observable associated with
every two-cycle in six dimensions. We make a natural guess for the commutation
relations of these operators, which reduces to the commutation relations of
Wilson and 't Hooft lines in four-dimensional SU(N) N = 4 super Yang-Mills
theory upon compactification on a two-torus. We then verify these commutation
relations by considering the theory at a generic point of its moduli space and
including in the surface operators only contributions from the light degrees of
freedom, which amount to N - 1 (2, 0) tensor multiplets.
