An organist is a musician who plays any type of organ. An organist may play solo organ works, play with an ensemble or orchestra, or accompany one or more singers or instrumental soloists. In addition, an organist may accompany congregational hymn-singing and play liturgical music.
The majority of organists, amateur and professional, are principally involved in church music, playing in churches and cathedrals. The pipe organ still plays a large part in the leading of traditional western Christian worship, with roles including the accompaniment of hymns, choral anthems and other parts of the worship. The degree to which the organ is involved varies depending on the church and denomination. It also may depend on the standard of the organist. In more provincial settings, organists may be more accurately described as pianists obliged to play the organ for worship services; nevertheless, some churches are fortunate to have trained organists capable of more elaborate "voluntaries" (the solo music before, during and after the service) and improvisation. As most churches can afford to employ only one musician, the organist is usually also responsible for directing and rehearsing the choir(s). In the twentieth-century, many pipe organs were replaced by pipe-less electronic and digital organs, often as a low-cost alternative to rebuilding older pipe organs.
In the English cathedral tradition the organist is now generally called "Director of Music", although their function is mainly in the training and direction of music rather than actual playing; there will generally be one or more assistant or sub-organists who play for most services and some recitals. Sometimes the organist will be assisted by an organ scholar. The post of organist at most of the great cathedrals includes recital work and choral training. Another function of an organist is often as teacher to future players. Few organists hold historically special positions such as Carol Williams who is the Civic Organist of San Diego, the last true Civic Organist position still active in this the USA.