Memory, as reflected in neural plasticity, is certainly not a functionally homogeneous process. Within the context of the mnemonic functions of the hippocampal system, this paper discusses two issues. The first concerns the appropriate conceptual approach to be taken in a neuropsychological analysis of memory. We conclude that a dimensional approach, emphasizing a quantitative analysis of individual mnemonic processes, has a significant advantage over the dichotomous classification of different types of memory. The second issue concerns the most appropriate way to describe the role of the hippocampus in mnemonic processes. On the basis of electrophysiological, neurochemical, behavioral, and computational analyses of hippocampal function, we suggest that its major role is the reduction of interference.