With Georg Solti and Leonard Bernstein, Erich Leinsdorf was among the pioneers of the complete recording of Gustav Mahler's Symphonies. The three labels for which the three great conductors recorded (Decca, CBS, RCA) were competitors, and in the 1960s public favors were disputed over a composer who, at the time, did not have the reputation he has today. These were certainly very important integrals, which still today serve as a point of reference for Mahlerian interpretation. Unfortunately, following the vicissitudes of the American RCA, the Leinsdorf integral has become unobtainable on the market. With this edition, we are publishing two of the Austrian conductor's most important achievements, precisely drawing it from that complete work: the Fifth and Sixth symphony, interpretations that still set the standard today, and which enjoy a sound quality of great beauty, which years have not dulled.