Keith Jarrett was only 29 when he performed this concert of solo piano improvisations at the Opera House in Cologne in January 1975. The first decade of his prodigious musical life had seen him collaborate with the likes of Charles Lloyd, Art Blakey and Miles Davis. His compositional skills were also highly regarded.

In 1974 his desire to make a solo piano album led to his departure from Columbia Records and the beginning of a very fruitful relationship with Manfred Eicher’s ECM label. Eicher was his travelling companion on the European solo tour that led him to Cologne.

The prelude to the performance is not what you would imagine. Jarrett arrived in the city sleep-deprived to find the Opera House had set up an inferior and out-of-tune version of the Bösendorfer piano he had requested. His wanted to cancel the performance but was talked out of doing so at the 11th hour.

He took to the stage just before midnight wearing a neck brace to cope with back pain that had been hindering him for weeks.

What unfolds next is a wonder of imagination and technique. The provenance of the stories he tells are a mystery he unravels in real time. The spontaneity compounds the magic. The audience is locked into his unerring search for the narrative thread. Every time he arrives at another exquisitely phrased melody, a new door opens.

From the shimmering notes of the opening melody to the rapturous exuberance of the coda, this is an intense lesson in the act of creation. The way the artistic process itself is preserved is perhaps the most remarkable aspect of this landmark recording. Its eloquent power is harnessed in an eternal present. The reverberations will go on forever.