Sixteen years have elapsed since the first satellite measurements of atmospheric temperature. These were observations of the lower stratosphere. Techniques have developed rapidly, and observations now extend from the surface to the mesopause. The instruments and techniques are briefly described and a review is given of the wide range of middle atmosphere research that has been based upon these measurements. The Nimbus 6 pressure modulator radiometer has made over 3 years' observations of upper stratospheric and mesospheric temperature, with weighting functions peaking at up to 80 km. The main results from this instrument and their relation to variations at lower levels are discussed. Temperature variations are generally smaller in the upper mesosphere than in the stratosphere. Planetary waves penetrate to this level in winter. There is a strong negative correlation between zonal mean temperature near the mesopause and in the upper stratosphere on both long and short timescales.