Peculiarities of adsorption, wetting, and condensation on heterogeneous (colloidal scale) solid surfaces have been analyzed. In terms of the classical theory of capillarity, a generalization of the Young law for heterogeneous surfaces was achieved. The relationship between adsorption, wetting, and condensation has been investigated. A series of new physical phenomena, a "quasi-cavitation" mechanism of heterogeneous condensation, double barrier nucleation, and endothermic wetting effect, are predicted and studied.