 Gradually becoming more and more interested, from the early 1950s on he began to seriously investigate Mahler's works and his life.He met Mahler's widow Alma Mahler in 1952, became a close friend of her daughter Anna, and interviewed other contemporaries of the composer.He carried out research in Europe and North America and over time accumulated a collection of materials which became one of the richest existing archives concerning Mahler and his epoch.