At the beginning, perhaps a few general comments are in order. All of us recognise the end purpose of our efforts in the area of physician typology. It is to identify those segments of the physician population which contain our best customer prospects. In the same process, of course, we are attempting to find means of screening out those physicians who are poorer prospects for prescribing our products. If our search for such criteria is successful, we shall then be able to improve the efficiency of product promotion by focusing in the directions of optimal prescribing potential.