  Granular and nanoscale materials containing a relatively small number of
constituents have been studied to discover how their properties differ from
their macroscopic counterparts. These studies are designed to test how far the
known macroscopic approaches such as thermodynamics may be applicable in these
cases. A brief review of the recent literature on these topics is given as a
motivation to introduce a generic approach called nanothermodynamics. An
important feature that must be incorporated into the theory is the non-additive
property because of the importance of surface contributions to the physics of
these systems. This is achieved by incorporating fluctuations into the theory
right from the start. There are currently two approaches to incorporate this
property. Hill (and further elaborated more recently with Chamberlin) initiated
an approach by modifying the thermodynamic relations by taking into account the
surface effects. We generalize Boltzmann-Gibbs statistical mechanics by
relaxing the additivity properties of thermodynamic quantities to include
nonextensive features of such systems. An outline of this generalization of the
macroscopic thermodynamics to nano-systems will be given here.
