Dominick Argento, a Pulitzer Prize-winning composer who was probably the most celebrated creator of new American operas between the heyday of Gian Carlo Menotti in the 1950s and the advent of Philip Glass in the 1970s, died Feb. 20 at his home in Minneapolis, where he had lived for six decades. He was 91.

His music publisher, Boosey & Hawkes, announced his death. The cause was not disclosed. Mr. Argento was always a force apart. He belonged to no compositional school, preferring a distinctly eclectic language that appealed both intellectually and emotionally to his audiences.