Whilst it seems that Adolphe Landry was the first to use the term demographic regime in the 1930s there still exists no simple, formal definition. Those who now use the concept appear to have the following in mind. It is applied to the long-term stability of demographic structures and the different ways in which nuptiality, fertility, mortality and migration may combine to create relatively slow population growth. The analogy is drawn from politics rather than ecology or the stages of development-modernisation; it implies order, stability, continuity, but also suggests variety among regimes that population growth may be regulated in a number of different ways each one of which can produce similar outcomes in terms of growth rates. This form of definition does raise a number of problems, however. Are demographic regimes to be thought of as conscious creations specifically designed to maintain a favourable balance between population and resources in the long term? And, if so, how are the different combinations of regulatory mechanisms created and adjusted, and to whose benefit is the regime ordered? Are some of the components of demographic regimes always more important than others? For example, does mortality set the parameters to which nuptiality and fertility merely adjust? How are demographic regimes transformed? To continue the political analogy, are they subject to revolutionary change, to complete overthrow during short periods of dramatic upheaval which are externally induced perhaps, or is slow internal adjustment more likely?