The central research topic of this chapter is embedded within three major fields of research, that is, sleep, memory, and cognitive aging research. Sleep is further characterized by changes in cerebral activity across the sleep-wake cycle. At a global level, brain activity decreases from waking to non-REM (NREM) sleep and returns back to waking levels during rapid eye movement (REM) sleep. Like sleep, memory is not a unitary system. In fact, there are several different classification schemes for human memory. In the context of sleep-dependent memory consolidation, an important distinction is usually drawn between declarative and non-declarative memory systems. Age-related cognitive decline is characterized by healthy and pathological processes in adult brain development. In this context, an important distinction is drawn between normal aging, mild cognitive impairment (MCI), and Alzheimer's disease (AD). Several psychiatric disorders such as Alzheimer's disease and depression are associated with disturbances of both sleep and memory.