This final report reviews the main theoretical and empirical developments concerning components of individual differences in human intelligence. The report is divided into three main sections. The first briefly reviews alternative approaches to understanding the nature of intelligence. The second provides the proposed componential metatheory, a view of human intelligence whereby intelligence is understood in terms of the functioning of various kinds of information-processing components, and in terms of the interactions among and automatization of these components. The basis of the componential view is the functioning of the metacomponents, or executive processes, which directly activate and receive feedback from other kinds of components; in particular, components of performance, acquisition, retrieval, and transfer. The third and main section describes various aspects of the componential theory and tests of this theory. This last section covers inductive and deductive reasoning. (Author/PN)