This book presents state-of-the-art knowledge regarding fluid and imaging biomarkers of neurodegenerative disorders, including Alzheimer disease and related dementias (ADRD). A cadre of the top experts in the field discuss the diagnostic and prognostic value of established and emerging biomarkers in ADRD, their ability to track or monitor disease progression or predict cognitive outcomes, and their potential as novel therapeutic targets. Biomarkers are discussed both in the context of specific disease mechanisms, including amyloid, tau, and synuclein pathologies, endothelial, vascular, neuronal, and synaptic injury, and glial reactivity as well as a wide spectrum of neurodegenerative disorders that encompass various pathologies. Multi-omics approaches in ADRD biomarker and drug target discovery including proteomics, genomics, and transcriptomics are covered. Importantly, the authors highlight the need to integrate biomarkers into various stages of ADRD drug development to accelerate drug discovery and approval. The book provides in-depth insight regarding significant progress in ADRD biomarker research over the last decade, addresses potential challenges in the translation of ADRD biomarkers into the clinic, and proposes important directions for future research.