ABSTRACT: For over a decade, one of the leading formal models of categorization has been the context model of classification proposed by Medin and Schaffer (1978) and elaborated by Estes (1986) and Nosofsky (1984, 1986). ... Recently, Kruschke (1990, 1992) elaborated the context model by incorporating key elements of it within the framework of a multilayered connectionist network ... . Kruschke's model, which we refer to as ALEX in this chapter, can be characterized as an exemplar-based network model. ... The purpose of the present article is to provide an overview of ALEX, discuss its relation to the context model, and illustrate applications of the model in a variety of category learning situations.