Since the introduction of the first commercial (temperature servo) device for quantitatively measuring heat flow into (or out of) a sample as it undergoes a transition, there has been considerable confusion about what name should be used to describe this analytical measurement (1). A wide variety of labels has been applied including Quantitative Differential Thermal Analysis (QDTA) (1,2,3), Dynamic Differential Calorimetry (DDC), Dynamic Enthalpic Analysis (DEA) and, of course, Differential Scanning Calorimetry (DSC). DSC has been the most accepted name largely because instrument manufacturers have used the term. With the introduction of other commercial devices, which also measure differential heat flow but are not based on the temperature servo approach , the confusion has increased. This confusion has been aggravated by the instrument manufacturers themselves who have often claimed unspecified advantages for their particular instrument. The manufacturer of the original commercial device, understandably, has attempted to limit the DSC definition exclusively to his design. He continues to claim that his instrument is the only “true DSC”.