This chapter outlines the cognitive architecture used by cognitive load theory, and provides a general indicator of its relevance to instructional design issues associated with multimedia instruction. Cognitive load theory has been one of the theories used to integrate our knowledge of human cognitive structures and instructional design principles. It is concerned with the elements of that theory and its general implications for multimedia learning, specifically words presented in spoken or written form along with pictures or diagrams. The chapter considers categories of knowledge from an evolutionary perspective, followed by an outline of those aspects of human cognitive architecture relevant to instructional concerns, also considered from an evolutionary perspective. The chapter discusses three categories of cognitive load: intrinsic cognitive load, extraneous cognitive load and germane cognitive load. All categories of cognitive load are concerned with the acquisition, storage and use of biologically secondary information.