  We present N=2 supersymmetry transformations, both in N=1, D=4 Minkowski and
anti-de Sitter superspaces, for higher superspin massless theories. It is noted
that the existence of dual versions of massless supermultiplets with arbitrary
superspin s may provide a basis for understanding duality in N=1, D=4
superstring theory. We further conjecture that the N=1, D=4 supergravity
pre-potential together with all higher superspin s pre-potentials are
components of an N=1, D=4 superstring pre-potential.
