An increased understanding of the predisposing genetics and complex pathogenic mechanisms of Alzheimer's disease have facilitated delineation of the long preclinical course and re-invigorated the search for disease-modifying treatments. Establishment of accurate blood-based biomarkers has enabled preclinical identification of early disease and permits trials of preventative treatment and quantitative monitoring of therapeutic effects. The broad range of therapeutic possibilities encompasses gene editing, enzyme activators and inhibitors, antisense oligonucleotides, and antagonists of receptors for inflammatory mediators.