Eunice Norton (1908-2005), great-great-grandstudent of Beethoven, gives a detailed, analytical tour of Bach's Well Tempered Clavier #12 in F, Bk I ( part 1, part 2part 3 ) and #13 in F#, Bk I (part 1, part 2) in several 1989 videos on YouTube.
"She made these videos when she was 80, and demonstrates Bach much as he likely sounded in his own time... One of her teachers in the 1930s was Artur Schnabel probably the greatest pianist of the 20th century. He, through his teachers and their teachers, was a very direct link back to Beethoven, who practiced the WTC every day and considered Bach to be the master. What Norton says about Bach comes directly from Schnabel and probably comes equally directly from Beethoven. She died in 2005 but she too had a number of students who continue the link."