The talk is devoted to experimental and theoretical investigations of structures and properties of self -assembled monolayer films of organic molecules with long aliphatic chains deposited on atomically flat surfaces . The reconstructed Au(111) facet and basal plane of highly oriented pyrolitic graphite (0001) are used as a substrates . The structural investigations have been performed by in-situ scanning tunneling microscope (STM) adapted to the liquid environment. It is revealed that the structures and proper ties (stability, melting behavior, tribological) of n-alkane films on Au(111) depend on the molecule length in a nonmonotonic manner. A one -dimensional model based on the misfit between periodicity of alkyl chain and Au(111) surface along <110> direction is developed for explanation of adsorption anomalies in n-alkane /Au(111) system. We also show that atomically flat surfaces modified by organic template can serve as a new subtrates for formation of new organic interfaces. The observed self -organized nanostructures are discussed in terms of adsorption and lateral interactions.