"Hans Knappertsbusch was in my opinion the greatest Wagner conductor of all time. His renditions were grandiose, dramatic and emotional. Unfortunately this kind of Wagner conducting has been somewhat unfashionable since his death in 1965. There are several releases of Der Ring des Nibelungen, Parsifal and Die Meistersinger von Nürnberg conducted by Knappertsbusch but this is his only Tristan recording. Recorded live in 1950, the sound is good for it's age. Günther Treptow who sings the part of Tristan was an underrated heldentenor. He is my favorite Siegfried and also does an impressive interpretation of Tristan. His voice is big, dark and warmer than some heldentenors. It is interesting that the Marke and Isolde of this recording, Ferdinand Frantz and Helena Braun, were actually a husband and a wife. Frantz was a famous bass-baritone, best known as Wotan. He has a huge, dark voice but his interpretative skills are limited. Braun is the least good singer of this recording, her mannerism is sometimes a bit annoying. Margarethe Klose who sings the part of Brangäne was one of the best mezzo-sopranos of the era. Paul Schöffler was best known as Hans Sachs. His voice is a bit too dark for the part of Kurwenal but his singing is first class. Apart from Herbert von Karajan's Bayreuth recording (1952) this is my favorite recording of Tristan und Isolde, in spite of the slight casting weaknesses."