Abstract
The Kondo effect in a disordered medium is investigated. The existing perturbation theories for static impurities and for magnetic ones are unified and examined in leading logarithmic order. When determining TK the competition of two effects are shown: the decrease of the density of states at EF decreases TK; diffusive processes increase it. TK depends in a non-monotonic way on the disorder. The experimental situation is discussed for both dilute magnetic alloys and metallic glasses.