The interest in better understanding tau function and dysfunction has steadily increased since the 1980’s when it was identified as the primary constituent of the pathological inclusions in Alzheimer’s disease (AD), known as neurofibrillary tangles (Brion et al., 1985; Delacourte and Défossez, 1986; Grundke-Iqbal et al., 1986a, b; Ihara et al., 1986; Kosik et al., 1986; Nukina and Ihara, 1986; Wolozin et al., 1986; Wood et al., 1986; Dickson et al., 1987). This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.