Alzheimer’s disease (AD), Parkinson’s disease (PD) and related neurodegenerative disorders are becoming increasingly more prevalent in the United States and globally due to the longevity revolution. The consequences of these diseases are grave, both for individuals and the global community, prompting concerns that rising healthcare costs have the potential to result in deleterious effects on national economies that could spell disaster unless disease-modifying therapies are discovered very soon. Fortunately, remarkable progress has been made toward elucidating mechanisms of AD since the discovery of the Abeta peptide in 1984, which launched the molecular era of AD research. That, coupled with the demonstration that tau is a building block of AD tangles in 1991, led to the understanding that AD, PD and most other neurodegenerative disorders are protein misfolding diseases, which has led to further clarity about mechanisms underlying AD. This has culminated in the identification of new targets for disease-modifying therapies as well as biomarkers for AD. Most recently, provocative data have emerged suggesting that the progression of AD may be due to the cell-to-cell spread of pathological species of tau and Abeta, thereby ushering in exciting new opportunities to arrest AD progression with immune therapies. Thus, the purpose of this meeting, which will be held in concert with a parallel meeting on “Parkinson’s Disease: Genetics, Mechanisms and Therapeutics,” is to explore these fundamental insights into mechanisms of AD and the opportunities they provide to translate this knowledge into meaningful interventions for AD.