Psychological research using time as a variable has been extensive since the era of Wundt and Ebbinghaus. The care of and research on dementia patients highlights a unique need for understanding and applying the concepts of time and space. This volume, unique in its development of a model for time-space orientation, proposes that understanding the needs of these patients is increased by consideration of the ^Idis^Rorientation caused by dementia. Included is a review of the history of time and time measurement, a survey of psychological literature using time as a variable across the life span, and a model of time orientation applied to persons who have developed dementia.Conditions leading to dementia are described, and a rationale proposed for the effects of time/space disorientation in behavioral disturbances. Suggestions for applications and future research are included. Scholars and researchers interested in time awareness and orientation, as well as professionals in psychology, sociology, and gerontology caring for dementia patients, will find the material here useful.