The study of administration proceeds within the framework of a taxonomy of human relationships, the breadth and content of which remain fluid. In large measure, when we speak of law we refer to a socially prescribed and sanctioned taxonomy of human relations. The analysis offered in this chapter is grounded upon the premise that clarification and refinement of a taxonomy of administrative relationships may result from the study of legislative enactments prescribing relationships between administrative agencies. It also reflects the supposition that at a time when the behavioral or human-relations approach to the study of administration is in ascendancy, such a review may provide an essential foundation for the contrasting of formality and actuality which is one of the characteristics of behaviorism. In the following pages we record and classify various kinds of inter-agency relationship prescribed by statute. We have attempted to employ the inductive approach, permitting the categories and gradations of relationship to emerge from the materials. But we are not unaware of the inevitable intermixture of the _a priori_. When fashioning economic regulatory legislation, Congress must heed the complexity of the industrial society to which the controls are to be applied, and of the bureaucracy through which regulation is to be accomplished. It will be possible to realize the legislative purpose only if the active co-operation and help of a wide variety of official agencies and private groups can be enlisted. And these must include the groups to be regulated.[659] Thus it is not surprising to find, upon examining a large number of emergency regulatory statutes enacted during the last twenty-five years, that they contain many provisions detailing the relationships which should prevail between the administering agencies and other groups, official, semiofficial, or private. Such provisions establish a variety of rights and obligations. They may have the effect of enlarging or constricting the discretion of a particular agency to interpret and pursue legislative policy goals. In the pages which follow we attempt to sort out and categorize such provisions. The confusing medley of statutory provisions for kinds and gradations of inter-agency relationship is perhaps best reduced to order by invoking the image of three overlapping spheres. [Illustration: permissive or mandatory solicitation or receipt or advice of a nonbinding nature mandatory performance in accordance with instruction of another agency joint pursuit of policy goals by co-ordinate agencies ]