I imagine that most people in Europe, when they think of modern American music (apart from jazz), think of the composers of the twenties and thirties and earlier who were the true pioneers in creating an American style—men like Charles Ives (1874–1954), Wallingford Riegger (1885–1961), Roy Harris (b.1898), Roger Sessions (b.1896) and Aaron Copland (b.1900). These men, together with the somewhat younger William Schuman (b.1910) and Samuel Barber (b.1910) and their contemporaries, still represent the high-water mark of American music. But, since they became known, two new generations of composers have sprung up and revolutionary changes in technique and esthetics have emerged.