The diseases of the central or peripheral nervous system are called neurological disorders. These disorders include epilepsy, Alzheimer's disease, and other dementias. Cerebrovascular diseases such as stroke, migraine, multiple sclerosis, Parkinson's disease, etc. are also considered as neurological diseases. A biomarker or biological marker is a cell, tissue, or body fluid cell that can be measured and evaluated to indicate a pharmacological response to a normal biological process, pathogenic process, or therapeutic intervention. Biomarkers characterize the progression of the disease from the earliest natural signs of the disease. Biomarkers assess the disease susceptibility and severity enabling prediction of outcomes, deciding interventions, and assessing the therapeutic responses. Based on clinical applications, biomarkers can be categorized as molecular biomarkers, cellular biomarkers, or imaging biomarkers. This book aims to shed light on some of the unexplored aspects of biomarkers. It presents researches and studies performed by experts across the globe on the topic in detail. It attempts to assist those with a goal of furthering their studies in the field of biomarkers and biomarker development.