Birgit Nilsson sings Brunnhilde. Dietrich Fischer-Dieskau sings Gunther. The orchestra is the Vienna Philharmonic, the conductor Covent Garden's Georg Solli. The music is, of course, Wagner's. The event is what a leading critic has described as the greatest achievement in gramophone history: the recording of the entire Ring Cycle. Seventeen Stereophonic Hours.

For the final eight days of the recording, a mobile television unit from the Austrian Television Service moved into a converted Viennese ballroom to tape the biggest production of its kind ever televised. Then along came a BBC film unit to add to the confabulation.

They returned with Sixteen Canned Hours—and several months' editing ahead of them. This is the result: the record of the record. The entire background of the operation is interspersed with interviews with the principal artists and studies of the technicians at work in the vast complexities of it all. It is an achievement of interest to many more than lovers of Wagner.