Edinburgh Playhouse, Five stars

Rock 'n' roll, Beat poetry and contemporary classical music aren't exactly staples of Edinburgh International Festival's programme. The appearance of composer Philip Glass and singer, poet and shamanic force of nature Patti Smith to pay homage to counter-cultural guru Allen Ginsberg, however, is a bold and unexpected move that should point the way for EIF's future.

The New York duo's opening performance of Smith's Notes To The Future before an audience of ageing hippies and young ­bohemians is all too appropriate in this respect. The evening is divided into four loose-knit sections. In the first, Smith reads words penned by both Ginsberg and herself, with Glass discreetly underscoring on the piano.

As Glass leaves the stage, Smith is joined by guitarist Tony Shenahen, who accompanies her on emotive renderings of songs from her back pages. Glass returns to play three solo miniatures before Smith rejoins him for some final excursions into disembodied poetics. All this is accompanied by back-projected images of Ginsberg, from young rake to Beat generation icon to wise old sage.

This only hints at the sheer power of a compendium of work that goes gloriously off-piste from the advertised programme, with Smith pre-empting each song with readings of several Robert Louis Stevenson poems for children culled from a book she bought the day of the gig in a shop opposite Stevenson's birth-place.

A sense of both their own and Ginsberg's mortality permeates the evening, and, while mournful and elegiac, the rolling thunder of Ginsberg's words becomes thrillingly transcendent in Smith's similarly unfettered delivery. By the end, Smith's arms are raised in an act of homage and salvation in a life-affirming evening to cherish.