This review deals with the historical development of a chemical kinetics and photochemical data base for use in atmospheric modeling. Initiated by the suggestion that the release of nitric oxide into the stratosphere from the exhaust gases of supersonic aircraft could seriously deplete stratospheric ozone, the quest for such a data base began in 1971. The present article traces the development of the detailed chemistry of the homogeneous gasphase reactions which control the levels of ozone in the stratosphere. It also includes coverage of the more recent heterogeneous chemistry which is believed to be involved in the Antarctic "ozone hole," as well as the background to the on-going establishment of a reaction rate data base for application to tropospheric chemistry and modeling.