This pioneering book covers a broad range of reversible causes of cognitive decline and dementia, ranging from the basic neuroscience of the condition to clinical manifestations and practice treatment implications. It offers something new to the field of dementia assessment and treatment by shining a light on the multiple comorbidities that compound the patient’s clinical presentation and exacerbate cognitive decline and by presenting differential diagnoses and the imperative to rule out reversible causes of cognitive impairment/dementia in one key text. Taking a global approach, chapters include mild cognitive impairment and the impact of drugs and substance abuse and other medication effects. The book goes on to look at depression and other psychiatric presentations, chronic pain, metabolic conditions, and tumors and other space-occupying lesions. Infectious diseases and other medical illnesses that affect cognition are explored, along with the impact of sleep disorders and delirium. The book concludes with a focus on applications and treatment when maximizing an older person’s functioning and assessing their cognition and/or their capacity. It is essential reading for clinicians, researchers, and specialist nurses in aging and dementia as well as students of neuropsychology/neurocognition, medicine, and health and social work.