  We show how the prescription of taking the absolute value of the fermion
determinant in the integration measure of QCD at finite density, forgetting its
phase, reproduces the correct thermodynamical limit. This prescription, which
applies also to other gauge theories with non-positive-definite integration
measure, also has the advantage of killing finite size effects due to extremely
small mean values of the cosine of the phase of the fermion determinant. We
also give an explanation for the pathological behaviour of quenched QCD at
finite density.
