Adler function from R^(e^+e^-) measurements: experiments vs QCD theory

An experimental motivated QCD analysis of the behaviour of the Adler D-function in the Euclidian region is described. It is stressed that by taking account of $b$-quark mass-dependent $\alpha_s^2$-effects one obtains better agreement between theoretical predictions and experimentally motivated behaviour of the D-function at large Euclidian momentum transfer. A more detailed analysis of QCD predictions, including information on quark and gluon condensates, requires more precise data on $e^+e^-\to{hadrons}$, particularly in the region $E<M_{J/\Psi}$ and $M_{J/\Psi}<E<3.6 GeV$. use of experimental determination of the D-function to test the generalized Crewther relation is outlined.