With the exceptions of Bartók and Messiaen, modern European composers have not shown a particular preference for the piano as the natural vehicle for major works. It has been left to American composers to continue writing works for the piano with the same confidence as the nineteenth-century masters. The list is impressive, ranging from Ives's extraordinary sonatas to Elliott Carter's fine Concerto, via Piston, Sessions, Barber, Cowell, Foss and Copland. The reasons for this American dominance in modern piano literature are complex, although the purely economic factor, that it is cheaper to perform a piano work than an orchestral one, probably influenced Ives's and Copland's generations. To this must be added the use of the piano in jazz, that peculiarly American phenomenon. Indeed the piano, in its more percussive vein, seems to be the quintessential sonority of American music. Looking at Copland's work we can see that piano sound clearly influences the nature of his orchestrations, as it did Ravel's. Some works began life as piano scores (the ballet Billy the Kid for instance), most of the orchestral works include a piano, and many use typical piano gestures—the opening of El Salón México for example. Conversely Copland's piano writing, like that of Beethoven, is influenced by the sounds of the orchestra, although never to such an extent that it prevents truly pianistic writing. The piano works are brilliantly realized in terms of the instrument and are virtuoso pieces, particularly in their rhythmic and sonorous subtleties.