I was fortunate to get into stratospheric chemistry at the early stages of the revolution in understanding of the chemistry of the ozone layer. I will review some of the historical work that led to our understanding of the ozone layer. I will follow the lead of P.K. Bhartia from the last talk and emphasize the ozone hole. I will examine the history of our understanding primarily from the theory side with some important digressions into the measurements. The ozone hole discovery was announced in 1985 and by 1987, we had several potential explanations and measurements that demonstrated which of these was fundamentally correct. This amazing rapid response was due to the decades of research that laid the foundation for explanation.