When Bunsen and Kirchoff observed the stars spectroscopically, they opened up a new field of observation, and stellar spectroscopy soon became a routine. What the astronomers discovered was a bewildering variety of stellar spectra, to the point of confusion and disarray. There was an urgent need for some order, for once order is established, theories about the evolution of stars, as well as their energy source, can be conceived and checked against observation. It was stellar classification that revealed to astrophysicists where the elements are synthesized and how stars evolve. However, it was not an easy ride.