This chapter reviews the clinical context and describes the functional-anatomic architecture of multiple memory systems including working memory (WM), declarative memory, and non-declarative memory. The anatomical substrates of memory include distributed networks of cortical and subcortical nuclei interconnected by white matter projection pathways. Memory impairments are comorbid with other cognitive and neurobehavioral problems. Disorders such as herpes encephalitis, which has a predilection for limbic and paralimbic cortical regions, may cause an amnestic syndrome associated with other neurobehavioral features, such as personality change and seizures. WM refers to the retention of information over brief intervals of time. Neuropsychological evidence suggests that there are two main types of dysexecutive syndrome, each reflecting dysfunction in the central executive system. One type involves marked perseveration, indicating decreased ability to disengage and shit attention, whereas the other is characterized by excessive distractibility, which reflects impairments in attentional inhibition.