Over the years that Angela Hewitt has recorded Bach for Hyperion records, it has gradually become clear that there has been an elephant in the room. Its unspoken name was The Art of Fugue, the monument of counterpoint left unfinished at Bach’s death. Hewitt wasn’t studying or playing it. Apart from being appallingly difficult, its music, she says, seemed remote, even boring.

Finally, with no other Bach monument left to scale, this most elegant British-Canadian pianist grabbed her elephant by the trunk. She scheduled a performance, in two instalments, at the Royal Festival Hall in 2012-13. She studied hard, thought hard. And with the score seamlessly unrolling on her iPad she outpoured playing of unusual distinction, even for her. Recorded last summer under studio conditions in Berlin, this album captures that interpretation on her trusty Fazioli in friendly and pellucid sound.

I won’t mince words. This Art of Fugue is marvellous. The variety and beauty of tone alone make compelling listening, bringing contrasts, clarity and warmth to Bach’s intellectual marvels. The fugal subjects pile up; they are inverted, augmented and turned inside out—permutations neatly documented in the pianist’s typically detailed booklet notes. Yet her fingers never make the results dry triumphs of engineering.

Each piece casts a specific mood, sombre, flighty or relaxed. Hewitt maintains, too, an innate sense of the pace required for letting the counterpoint’s individual voices breathe. Dotted rhythms and decorative flourishes are polished and placed with infinite care, especially noticeable in Contrapunctus 6, labelled “in stylo Francese”. Here and elsewhere, in his own recording from 2008, Pierre-Laurent Aimard—French himself—appears very tightly corseted.

Throughout, Hewitt’s interpretative decisions are almost all helpful and wise. The one exception for me is her addition of a chorale prelude following the last unfinished fugue, which performers usually leave dangling so poignantly in mid-air. I find the chorale an intrusion, but there can’t be any doubt, surely, about the expressive benefits of performing Bach’s epic on a modern concert grand—other options are possible—or the radiant majesty and humanity of her playing. The Art of Fugue is an elephant no more.