In the late 1960s, while teaching at , Professor Robert Resnick (1.2.2, 1.2.5) noticed that while students could solve classical physics problems, they often stumbled when faced with the "common sense" contradictions of Einstein’s universe (1.2.6, 1.5.4). This led him to write Introduction to Special Relativity (1968), a text that would become a staple for physics students worldwide (1.2.8, 1.4.9) .