The origin of the concept of the auroral substorm has its roots in the work of the pioneers of solar-terrestrial physics, such as Birkeland, Stormer, Chapman and Alfven. However, the International Geophysical Year (IGY) in 1957-1958 was an epoch-making event regarding the development of auroral physics. For the first time, auroral scientists could observe auroral activity on a global scale. In 1958, I joined the Geophysical Institute as a graduate student of Sydney Chapman, who had been working on the main phase of geomagnetic storms for a long time. Together, we developed a theory on substorms that has endured more than three decades. After the advent of satellites, auroral studies advanced greatly; auroral substorms are now understood to be one of the manifestations of magnetospheric substorms, which turn out to be the cause of the main phase of geomagnetic storms. A new result (my final JGR paper just accepted for publication) will also be mentioned.