Measurements of ozone from rocket observations of the 1.27μ band are reviewed. The technique of using ground-based measurements to infer altitude profiles of the 1.27μ emission at twilight is illustrated. A comparison of altitude distributions derived from ground-based twilight observations with direct rocket measurements of the distributions demonstrates that ground-based observations provide a practical method to monitor the twilight altitude distribution of O2(1Δg). These O2(1Δg) altitude distributions can be easily converted into ozone distributions. A two-layer structure is present in the altitude distribution during most months of the year, but may be absent in midsummer. An observation on January 16, 1971, indicated that midsummer conditions may occur during a stratospheric warming. Preliminary observations indicate a strong seasonal variation of the upper ozone layer at 85 km with peak concentrations in excess of 1.3×108/cm3 in midwinter and less than 0.3×108/cm3 in midsummer.