Classical density functional theory (DFT) is based on the idea that the free-energy is a functional of the statistically averaged one-body density. We show that the two-body correlation functions are also density functionals and that they can be explicitly calculated for hard-spheres in specific geometries. By introducing these concepts into DFT we obtain both new approximation schemes and an alternative view of the existing theoretical framework. 

In this talk we will show how to obtain the two-body correlation functions, present an improved mean-field approximation for treating both repulsive and attractive systems and, finally, show how density profiles can be obtained directly by integrating the interparticle forces.