The correspondence in the years 1913 to 1916 pertains in part to Brecher's new translation of Gustav Mahler's version of Carl Maria von Weber's Oberon, the premiere of which Brecher conducted in Cologne in 1913; and also Brecher's preface for the text published by Universal Edition. Several of Brecher's letters contain musical notations by him. A single letter from 1934 (the only item that dates past 1917) is a plea for advice on behalf of the music critic Hans Heinz Stuckenschmidt, who, as a result of recent Nazi measures, had been barred from exercising his profession in Germany.