The basic principle underpinning DSC is that a sample is subjected to a heat signal and the response measured in terms of the energy and temperature of the thermal events that take place over the temperature range or time interval under study. The temperature profile may be in the form of heating, cooling, or an isothermal program, with heating being the most widely used approach. Consequently, although the most common use of the technique, certainly within the pharmaceutical sphere, has been to study melting responses by heating the sample at a controlled rate, many studies have also been performed on crystallization, glass transitions, and kinetic reactions such as curing. It should be borne in mind that the most common use of DSC in a global sense is for the characterization of polymers; hence, much of the theory, and indeed the hardware, has been developed with this application in mind. However, the principles involved are equally applicable to pharmaceuticals, inorganic materials, ceramics, and biological systems.