Jan Garbarek / The Hilliard Ensemble: Mnemosyne

Half a decade ago, the visionary in Manfred Eicher met the marketing man head-on and the first collaboration between ECM's most popular artists - and an album called Officium - bridged the outwardly alien worlds of mediaeval ecclesiastical vocal harmony and Jazz saxophone. Garbarek's purity and economy of sound and his independence from the rhythmic history of Jazz allowed his saxophones to sing a fabulously evocative descant to the four Hilliard vocalists stunning recreations of vocal music before the Renaissance.

Officium became a worldwide success, and this year the collaboration is on tour around the world to support a new double CD recorded once again in the Austrian alpine monastery of St Gerold that mid-wifed Officium.

Mnemosyne means memory in pre-Christian Greek, and the five musicians work with more than 2,000 years of Western music - sometimes whole pieces, sometimes just fragments scribbled in the margins of a psalter, or, this time, new pieces by Garbarek himself that demand this most ancient of styles reinvent itself as improvisation and jazz.

Officium remains a stunning, breakthrough recording. For the jazz fan, Mnemosyne moves the magic up a notch. If you haven't had the experience yet, do yourself the favour soon.