Neurodegenerative diseases cause disability and death in millions of people worldwide. [1] The cost of treating these illnesses exceeds a quarter of a trillion dollars in the United States alone [2]. Despite numerous approaches having been tested in clinical trials, available therapeutic options for neurodegenerative diseases remain limited and many syndromes lack even symptomatic treatment options. Disease-modifying therapies that can alter the underlying biology and slow or arrest disease progression are urgently needed. One approach is targeting tau proteins, which have been implicated in a variety of neurodegenerative diseases through both clinical/pathological correlations as well as genetic studies.