In a logistics system the number of possible applications of qualitative and quantitative modelling efforts is practically infinite. The situations or problems which can be analysed range from micro operations (e.g., analysing alternative order picking systems) to macro planning issues (e.g., determining the number and location of warehouses to be employed in a future distribution system). This range of potential applications not only reflects the scope of the models (micro to macro) but it also incorporates another relevant dimension: planning. The planning axis is anchored at one end by operations models which are constructed to analyse daily operating practices. The other end of the continuum is represented by long range planning models. These models are used to aid logistics managers in their attempts to design systems to cope with the future. In many situations exact classification of individual models along these two dimensions is difficult. However, this categorisation is a useful framework within which to view the scope of the modelling discussed in this paper. This presentation will focus on the macro planning models that are being employed both in military and industrial logistics to aid the systems planner in his attempts to structure logistics systems for the future.