This book describes the processes involved in the aging of the human mind, the role of memory, cognitive impairment, and changes in information processing in older people. It describes the role of nutrition and physical exercise in keeping the mind healthy. According to WHO, 55 million people live with dementia worldwide, and there are 10 million new cases every year. Alzheimer disease is the most common form of dementia and may contribute to 60–70% of cases. Dementia has physical, psychological, social, and economic impacts on people living with dementia and their caregivers, families, and society. Older people with dementia need individualized care and extended and assisted living care with elaborate planning. Other diseases of the mind that may affect the elderly are delirium and mood disorders.