Many thanks for the alert on the issuing of the classic Deryk Cooke lecture on the Mahler 10 and Golschmidt's performance, which were the watershed for the symphony. It was this lecture with its musical illustrations, as played for Alma Mahler, that led her to approve the progress on the Cooke performing edition of the draft. These, along with the 1924 facsimile, made the 10th possible for our time. I didn't know about it before but now have just ordered it from MDT.