Dementia is a common, chronic and progressive illness. Many different types of dementia exist. It is important to have knowledge of the various dementia presentations so that the clinician can differentiate one type from another. Past and current approaches of classifying dementias are reviewed in this paper. The past cortical/subcortical scheme is reviewed as well as the current synucleinopathy/tauopathy scheme. This paper focuses on the most common synucleinopathies and tauopathies including Alzheimers Dementia, Dementia with Lewy Bodies, Parkinsons Disease, Frontotemporal Dementia, Progressive Supranuclear Palsy, Multiple System Atrophy and Corticobasal Ganglionic Degeneration. We systematically approach each dementia and review cognitive, psychiatry and neurological features of each. We also compare and contrast each dementia and the synucleinopathies and taupoathies alike. Our goal is to provide the clinician with sufficient knowledge to competently and confidently diagnose a patient who presents with progressive cognitive decline and deterioration in functioning.