  We discuss the properties of four-point functions in the context of the
correspondence between a classical supergravity theory in the bulk of the Anti
de Sitter space and quantum conformal field theory at the boundary. The
contribution to a four-point function from the exchange of a scalar field of
arbitrary mass in AdS space is explicitly identified with that of the
corresponding operator in the conformal partial wave expansion of a four-point
function on the CFT side. Integral representations are found for the massless
vector and graviton exchanges. We also discuss some aspects of the four-point
functions of Tr F^2 and Tr F F^* (`dilaton' and `axion') operators in the N =4
supersymmetric Yang-Mills.
