Better knowledge of the preclinical phase of Alzheimer's disease and of the symptomatic pre-dementia stage designated "mild cognitive impairment" will require considerable progress in our understanding of neuropsychological processes. The results of studies suggest that impaired performance in memory tests may serve as a marker for Alzheimer's disease. The best current predictors include stringent tests of episodic memory and recognition tests. The early stages of Alzheimer's disease also seem to involve subtle deficits in semantic memory and attentional processes. Face recognition and denomination seem to be useful tools. Greater accuracy and precision in the transitional zone between healthy aging and the first manifestations of Alzheimer's disease will require work combining data on neuropsychological profiles and neuroimaging.