FOR one night (13 October) only, In Restless Dreams: The music of Paul Simon (Cert. 12A) is showing in cinemas, for the singer-songwriter’s 82nd birthday. Then, from 28 October, it will be available on Blu-ray and digital.

This documentary is directed by the renowned Alex Gibney, whose work includes Mea Maxima Culpa: Silence in the house of God (Arts, 15 February 2013). It’s a serious reflection on Simon’s compositions, redolent as they are with biblical imagery and spiritual quest. The idea of a film really took off once Simon began working (after a dream) on Seven Psalms, now an album. It is no surprise after a career-long preoccupation with matters spiritual: songs based on the Beatitudes, a Bach hymn, a Christmas carol, and even (a clever pun) the belief that we all will be received in Graceland.

Much will be familiar to aficionados of the performer. There are plenty of Simon and Garfunkel numbers (“Sound of Silence”, “Bridge Over Troubled Water”, etc.) and details of their break-up. Twists and turns follow Simon’s subsequent career. Never solely a troubadour of melancholy, he has sometimes engaged controversially with African and Latin musical traditions and introduced new and joyful harmonies into a divided world.

Interwoven throughout the picture are the psalms that Simon was working on. As such, it feels like a pilgrimage. From standing alone without belief (“Kathy’s Song”) to one of his psalms stating that he continues to have “reasons to doubt there is a case to be made”, the singer nevertheless keeps searching. Time and again, it is evident, as in “The Sound of Silence”, that the vision that was planted in his brain still remains.

Seven Psalms (no more than earlier compositions) is not without hope. Like its Hebrew predecessor, they are often songs of praise rather than lament. This raises the question whether these are the musings of an old man face to face with his mortality. Simon says that these new songs are an argument with himself about belief or not. In “Wait”, he sings: “I’m not ready. I’m just packing my gear” while acknowledging “Heaven is beautiful. . . It’s time to come home.” Another psalm hopes that the gates won’t be closed before he receives forgiveness.

This 210 minute-long biography has gaps. No mention, for instance, is made of his failed stage musical The Capeman. Astonishingly, in a film (prompted by involvement with an overtly religious-titled album), neither Simon’s Jewish background nor his interaction with a predominantly Christian culture is explored. Many of his 1960s performances were in Britain, where he was befriended by Judith Piepe, a Jewish refugee who had become an Anglican. Later, Zeffirelli asked him to write the music for his film Brother Sun, Sister Moon about St Francis. Simon declined that invitation, but work for a while with Leonard Bernstein on his Mass.

Those omissions aside, Simon’s life and output are a glorious occasion to revel in the songs of someone who plumbs the mysteries of the soul, spreading rumours of God with its hints through music that there is so much more than we can ever tell.