The field strength superfield of IIB supergravity on AdS(5) x S-5 is expand
ed in harmonics on S-5 with coefficients which are D = 5, N = 8 chiral supe
rfields. On the boundary of AdS(5) these superfields map to D = 4, N = 4 ch
iral superfields and both sets of superfields obey additional fourth-order
constraints. The constraints on the D = 4, N = 4 chiral fields are solved u
sing harmonic superspace in terms of prepotential superfields which couple
in a natural way to composite operator multiplets of the boundary N = 4, D
= 4 superconformal field theory. (C) 2001 Published by Elsevier Science B.V
.