Introduction Martin L. Perl was the recipient of the 1995 Nobel Prize in physics for his discovery of the Tau Lepton, based on a 16-year history (1963-1979), when all experimental measurements agreed with the hypothesis that the Tau was a lepton produced by a known electromagnetic interaction (Perl et al., 1975; Perl, 1997). The objective of this chapter is to present a brief account of the discovery of the Tau Lepton in order to understand the nature of science (NOS) and then draw implications for teaching science.