  We study the boundary limit of the bulk isometries of AdS x S. The
superconformal symmetry is realized on the coordinates of the AdS boundary, the
fermionic superspace coordinates, and the harmonics on the sphere. We show how
these may be related to the coordinates of an off-shell harmonic superspace of
SCFT living on the boundary. In the special case of d=4, N=2 super Yang-Mills
theory, a truncation of the N=4 SYM dual to Type IIB string theory compactified
on AdS_5 x S^5, we identify the bosonic space SU(2)/U(1) of the N=2 harmonic
superspace (known before as auxiliary) with the S^2 submanifold of the S^5.
