42 participants from China, France, Norway, Russia, Spain, and USA attended the meeting. A total of 22 papers were presented. They covered a wide range of topics: underwater acoustics, transducer technology, new solutions to sound propagation problems, sound propagation in multi reflection environments, and applications of ultrasound in industry. The papers were presented in 5 oral sections. The presentation time allowed for each presentation was 20 minutes.

A tradition in these symposia has been to leave some time around noon to go skiing, so also this year. The weather was good, and the nearby "løyper" and downhill slopes at Geilo offered possibilities at all levels of ambition. This, followed by lunch, allowed the participants to meet fresh for the afternoon sessions.

It is the aim of the organizers to attract students at master and doctoral levels to present their work. The Norwegian Physical society must be acknowledged for their financial support to students who attended the meeting.

The proceedings contain 9 of the presentations. A separate index for the papers has been added. There was no page limitation for the manuscripts. The proceedings are also available as a CD, ISBN 978-82-8123-012-5. A zip-file with all the papers can also be downloaded here.

The organizers would like to thank sincerely the speakers and participants for making the meeting an interesting and enjoyable event. Special thanks to the chairpersons, who prevented the sessions to stray too far from the time schedule.

The Acoustics and Optics group of the Norwegian Physical Society plans to organize a new meeting in the year 2013. This will be the 36th in the series. Invitations will be sent early in the autumn of 2012.

Ulf Kristiansen was the coordinator of the Geilo 2012 meeting. Rolf Korneliussen will be the coordinator of the 2013 meeting.