  We discuss various details of our derivation of the exact expression for the
Adler D function in N=1 supersymmetric QCD (SQCD). This exact formula relates
the D function to anomalous dimensions of the matter superfields. Our
perturbative derivation refers to the D function defined in terms of the bare
coupling constant in the case of using the higher covariant derivative
regularization. The exact expression for this function is obtained by direct
summation of supergraphs to all orders in the non-Abelian coupling constant. As
we argued previously, our formula should be valid beyond perturbation theory
too. The perturbative result we present here coincides with the general formula
order by order. We discuss consequences for N=1 SQCD in the conformal window.
It is noted that our exact relation can allow one to determine the (infrared)
critical anomalous dimension of the Seiberg M field present in the dual theory.
