During her career, Swiss-born soprano Lisa della Casa was known for her engaging portrayals of Mozart and Strauss roles, particularly Strauss' Arabella. She began her studies at the age of 15 with Margarete Haeser, who remained her only teacher. Della Casa made her debut as Cio-Cio-san in 1941 in Solothurn-Biel and in 1943 became a member of the Zürich City Theater. In normal times she no doubt would soon have been singing in houses in Germany, Austria, and Italy as well, but she remained in neutral Switzerland until after World War II ended in 1945. One of her first major appearances outside Switzerland was at the Salzburg Festival in 1947. Engaged for that production on the recommendation of Maria Cebotari, she sang the part of Zdenka in Strauss' Arabella. She was engaged right away to return the following year for another Strauss role, that of the Countess in Capriccio. Della Casa became a member of the Vienna Staatsoper in 1947, but continued singing with the Zürich City Theater until 1950. In Zürich she sang a wide variety of roles: Pamina in The Magic Flute, Gilda in Rigoletto, and, unusually, Serena in Porgy and Bess (the Gershwin estate's insistance on all-black casting for that opera has not been followed in Europe as carefully as in the United States). She also sang a noted world premiere in Burkhard's Die schwarze Spinne as "The Young Woman" (1949) and created the triple role of the female leads in Gottfried von Einem's Der Prozess (1953). She made her British debut as the Countess in Mozart's Nozze di Figaro at Glyndebourne in 1951, and sang the title role of Strauss's Arabella for the first time at her Munich debut the same year. Arabella became her signature role. Her first appearance at Covent Garden was in that role on a tour with the Bavarian Staatsoper. Critics found in her voice the "spring and silver" that Strauss said he called for in such parts, and her attractive and elegant looks and unmannered acting style made her an audience favorite. She sang regularly at the Metropolitan Opera from 1953 to 1968, again appearing as Mozart's Countess. Of Mozart's heroines, she excelled in Donna Elvira, Donna Anna, Pamina, and Fiordiligi. She sang Chryothemis in Strauss's Elektra, in Ariadne auf Naxos, and even tried Salome (an attempt she admitted was an experiment). Since she had a wide range, she became one of the few singers to excel, in turn, in all three of the major parts in Der Rosenkavalier: Sophie, Octavian, and Die Marschallin. In 1952, she received the honorary title of Kammersängerin of Austria. She was invited to sing at the 1952 Bayreuth Festspielhaus, where she appeared as Eva in Die Meistersinger. She was, however, bothered by the lingering sense of the darker side of German nationalism she sensed at that shrine to Richard Wagner and turned down all further requests to sing there. She had a reputation as a thoughtful, highly principled artist and person. She was known for her criticism of the dishonorable aspects of the "music business" and loathed the intrigues, jealousies, and cabals that often infested the operatic world. She also felt that star egos prevented major singers from working together as ensembles. She retired from singing unexpectedly in 1974.