Radar has been used by meteorologists for 30 years or so but it is only during the latter half of this period that the full measure of its versatility has come to be recognised. Operationally important techniques have been or are being developed to identify and track severe storms, to provide warning of tornadoes, to measure and forecast rainfall quantitatively, and to measure winds, turbulence and wind shear. At the same time research meteorologists are using specialised radar techniques to investigate many poorly understood aspects of atmospheric behaviour : to identify the physics of clear air turbulence, the dynamics of fronts, the structure of the atmospheric boundary layer, the three-dimensional airflow and trajectories of hailstones in thunderstorms, and the patterns of precipitation within mid-latitude depressions. Studies such as these are giving fresh impetus to a branch of meteorology, mesoscale meteorology, which largely because of the difficulty of obtaining definitive observations has hitherto been a neglected field. This review highlights the strengths and limitations of radar as a tool for observing the atmosphere and attempts to provide a balanced view of its many applications in meteorology.