Natalie [Natalia Anna Juliana] Bauer-Lechner (Penzing, Vienna, 9 May 1858 – Vienna, 8 June 1921) was an Austrian violist who is best known to musicology for having been a close and devoted friend of Gustav Mahler[1] in the period between 1890 and the start of Mahler's engagement to Alma Schindler in December 1901. During this period, she kept a private journal which provides a unique picture of Mahler's personal, professional and creative life during and just after his thirties, including an exclusive preview of the structure, form, and content of his third symphony.