In its series on air pollution research, the European Commission, DG XII, has published a report on "Polar stratospheric ozone". The book collates the proceedings of the third European symposium on "Polar stratospheric ozone research", held in Schliersee, Germany, on 18-22 September 1995. The book contains individual contributions to the symposium, which range across many topics in stratospheric research. These contributions are the result of the SESAME campaign (second European stratospheric Arctic and mid-latitude experiment), supported by DG XII, as part of the Community's specific RTD programme in the field of the environment and climate. Most of these projects took place in the winter of 1994/1995, which was very cold, and therefore ideal for the observation of polar stratospheric clouds.