Even allowing for the fact that these were demonstration records when they first appeared, the sound on this CD is astonishing in its lifelike presence and its warmth. As nobody has surpassed Knappertsbusch to this day as a Wagner conductor in the inevitable sweep and grandeur of his direction, I need hardly say that this is a marvellous issue. The thrust and energy of the Dawn and Rhine Journey are matched by the tragic force of the Funeral March and the sheer sensual power of the warmly sustained Prelude to Tristan, where tempo changes and the surge of the performance are never put in the way of its structural coherence. Then, to have Nilsson's gleaming voice and heartfelt interpretation of the Liebestod to crown it is as much as one can ask for. George London is, by today's weaker standards, a truly heroic Wotan though not a greatly subtle one. Even so, his glorious voice fills the music with rich tone as few of his successors have done. Flagstad's ''Ich sah das Kind'', beautifully sung, is perhaps a little too cosy, not sufficiently seductive.'