Unearthing a never-before-heard studio recording by Bill Evans in a tape archive in Germany is akin to discovering another Caravaggio.

Evans is one of the most celebrated jazz musicians of the 20th century, the harmonic catalyst on Miles Davis's Kind of Blue, and the pianist who set the tone for all the piano trios that would follow. So even a poor-quality bootleg would be a welcome addition to his discography.

However, this double CD (or limited edition double LP) is much more than that: it is a lost studio session, an opportunity to hear the great man in pristine high fidelity at a pivotal point in time.

Until now there has been just a single recording of this particular version of Evans's long-standing trio (with bassist Eddie Gomez and drummer Jack DeJohnette): 1968's Live at the Montreux Jazz Festival, which won a Grammy the following year.

Now it turns out that, following their triumphant appearance at Montreux, the trio decamped to Villingen in Germany’s Black Forest to record with the influential producer and recording pioneer Hans Georg Brunner- Schwer.

About two hours of material was recorded on the day, mostly drawn from the trio's regular repertoire of standards and Evans originals, including Very Early, Turn Out the Stars and the gorgeous title track, alongside some lesser-played selections, including Baubles Bangles and Beads and You Go to My Head.

Evans favoured live recordings throughout his career, and it’s the live ones, particularly the earlier, iconic performances from the Village Vanguard, upon which his reputation principally rests.

So this studio session – while a priceless document that will be greedily devoured by collectors and completists – is not where you would start an exploration of the art of Bill Evans.For that, check out Sunday at the Village Vanguard or the live recording the trio made at Montreux just five days earlier. But you completists, knock yourselves right out.