Yang-Mills and D-instantons

In this paper, which is written at an elementary and pedagogical level, we discuss general aspects of (single) instantons in SU(N) Yang-Mills theory, and then specialize to the case of N =4 supersymmetry and the large-N limit . We show how to determine the measure of collective coordinates and comput e instanton corrections to certain correlation functions. We then relate th is to D-instantons in type IIB supergravity. By taking the D-instantons to live in an AdS(5) x S-5 background, we perform explicit: checks of the AdS- CFT correspondence.