A new software package (THESEUS) has been assembled for the analysis of the DSC data, concerning the thermal denaturation of biological macromolecules. The system is useful to obtain accurate physico-chemical information, bypassing the casual and systematic errors, very common in these experiments. It can also be used for handling data from other instruments and methodologies giving thermodynamic, spectroscopic or other kind of data as a function of temperature. Because many of the researches in this field are of exploratory nature and continuously new unfolding mechanisms are described or hypothesized in the current literature, we have written and assembled this powerful and flexible program of general applicability, in order to put the operator in a position to control each step of the calculation procedure and use his own experience for choosing the better way to solve unexpected problems.