Patti Smith met Allen Ginsberg when she was 22, and he bought her lunch thinking she was a pretty boy. Philip Glass composed music for Ginsberg's poems and they performed together often: Ginsberg reading, Glass noodling on the piano. Smith and Glass kept vigil as Ginsberg was dying from cancer. These three important American artists go back a long way, and the well-travelled tribute that Smith and Glass brought to the Edinburgh international festival made a poignant snapshot of intertwining lives, shared inspirations and the spirit of a heady generation.

The show is called The Poet Speaks, which applies to both Ginsberg and Smith. There's no question of mimicry here: Smith is a magnetic performer and spoke Ginsberg's words in her own vivid voice. Through the fiery verses of Wichita Vortex Sutra and Footnote to Howl, her flat vowels rose from conspiratorial whisper to urgent drone; to rich, earthy drawl. At times she lapsed into half-song, following Glass's shifting chords; elsewhere, her voice cracked with emotion that still felt fresh.

Despite her punk-priestess moniker, Smith is as warm as Ginsberg was provocative. She sang her own folksy songs with guitarist Tony Shanahan, and read poems by Robert Louis Stevenson. Stevenson is one of her childhood favourites, and his awe for the natural world was another link between her, Ginsberg and his hero, William Blake.

Glass played a solo piano set with his unique combination of messy and mechanical delivery. The evening closed with Smith's anthemic People Have the Power. Her parting words: "Don't forget to use your voice." Ginsberg once persuaded her to perform again after a long period away from the stage. The message was heartfelt.