The cellos are a critical part of orchestral music; all symphonic works involve the cello section, and many pieces require cello soli or solos. Much of the time, cellos provide part of the harmony for the orchestra. On many occasions, the cello section will play the melody for a brief period of time, before returning to the harmony. There are also cello concertos, which are orchestral pieces in which a featured, solo cellist is accompanied by an entire orchestra.
