Available measurements of thermodynamic properties (enthalpy, Gibbs free energy and volume) of mixtures of water with 2-butoxyethanol at 25-degrees-C are discussed, with emphasis on the concentration dependence of the excess functions, and on the role played by water. The data support the view that in the water-rich concentration range the nonpolar groups of the alcohol molecules introduce labile, highly cooperative, energy-low structures in water. At lower water concentrations, exposure of nonpolar groups to water appears to be minimized by formation of micellar-like alcohol structures.