This paper compares four current theories of expertise with respect to chess players' memory: Chase and Simon's chunking theory, Holding's SEEK theory, Ericsson and Kintsch's long-term working memory theory, and Gobet and Simon's template theory (Chase, W.G., Simon, H.A., 1973a. Perception in chess. Cognitive Psychology 4, 55–81; Holding, D.H., 1985. The Psychology of Chess Skill. Erlbaum, Hillsdale, NJ; Ericsson, K.A., Kintsch, W., 1995. Long-term working memory. Psychological Review 102, 211–245; Gobet, F., Simon, H.A., 1996b. Templates in chess memory: a mechanism for recalling several boards. Cognitive Psychology 31, 1–40). The empirical areas showing the largest discriminative power include recall of random and distorted positions, recall with very short presentation times, and interference studies. Contrary to recurrent criticisms in the literature, it is shown that the chunking theory is consistent with most of the data. However, the best performance in accounting for the empirical evidence is obtained by the template theory. The theory, which unifies low-level aspects of cognition, such as chunks, with high-level aspects, such as schematic knowledge and planning, proposes that chunks are accessed through a discrimination net, where simple perceptual features are tested, and that they can evolve into more complex data structures (templates) specific to classes of positions. Implications for the study of expertise in general include the need for detailed process models of expert behavior and the need to use empirical data spanning the traditional boundaries of perception, memory, and problem solving.