Lidar sounding of ozone and other atmospheric constituents has proved to be an invaluable tool for atmospheric studies. The ozone lidar systems developed at Garmisch-Partenkirchen have reached an accuracy level almost matching that of in situ sensors. Since the late 1990s numerous important scientific discoveries have been made, such as the first observation of intercontinental transport of ozone and the very high occurrence of intrusions of stratospheric air into the troposphere.