The medial temporal lobe (MTL) is classically thought to subserve long‐term memory exclusively. Contrary to this view, convergent evidence from animal lesion studies, functional neuroimaging, and neuropsychological patients now implicates the MTL in working memory and high‐level perceptual processes in addition to long‐term memory. Given this new evidence, it has been proposed that anatomical delineations between high‐level cognitive processes may be misleading for our understanding of how the brain supports mnemonic functions. Instead, a model in which visual representations become hierarchically more complex as one moves anteriorly from the occipital lobe through the MTL seems to better fit the available evidence. According to this view, the engagement of the MTL will occur when a stimulus is sufficiently complex, regardless of the cognitive process involved. Evidence from lesion studies for this representational‐hierarchical theory is reviewed, and the implications for our understanding of memory and forgetting are subsequently discussed.