This monograph represents the results of an attempt to construct at least one portion of a theoretical framework for describing and analyzing the performance routines used by the native actor to realize his competence to make culturally appropriate decisions. In general the concern is to describe in theoretical terms the structure and operation of two types of information processing rules (IP rules) and some of the principles underlying their organization into information processing systems (IP systems). Chapters 2 through 5 present a formal theory of code rules along with several algorithms that can be used in their construction and analysis. Chapter 6 presents the beginnings of a formal theory of marking rules. Chapter 7 is concerned with some of the general principles underlying the integration of IP rules and other operations into IP systems. This chapter also attempts to provide a concrete illustration of the structure, operation, and description of natural IP rules and systems, and to exemplify the application of theoretical notions developed elsewhere in this monograph to specific ethnographic problems, particularly in the area of semantics. The three theories discussed here are illustrated by examples from a study of the Balangingi' Samal address system. (Author/AM)