||In this thesis, we analyse both the theoretical and the empirical determinants of household debt and public debt, or, more generally, the determinants of saving of these entities. A short survey of the relevant theoretical and empirical literature is presented in the opening chapters. In the second part of the thesis, the tax smoothing model is extended by abandoning the assumption of a benevolent social planner. The main result of the model is a demonstration of the fact, that voters can vote over public budget decits in order to shift relatively high taxation of income into periods in which their income is relatively low. Through this channel, changes in income inequality can be indirectly reflected in public saving.