The world wide distribution of total ozone and its changes with season are discussed as well as the variability on different time scales. A climatology of the vertical ozone distribution is presented and an attempt is made to derive some inference on ozone transport by the general circulation and its interaction with photochemical processes. It is found that longer observational series in an improved network are needed for puttting such a derivation on a firmer basis. The observed year-to-year changes of world wide total ozone and of the vertical distribution indicate the importance of the quasi-biennial variation of the circulation in the tropical stratosphere for the poleward ozone flux. The suggested variation of ozone concentration in the upper stratosphere with the sunspot cycle must be further substantiated.