The more one listens to Alkan’s music, the more one realises what an extraordinary composer he is. Though the three pianist-composers have many things in common (Alkan even lived in the same Paris square as his friend Chopin), his voice is as distinct from Chopin as Chopin is from Liszt and Liszt from Alkan.

This sixth volume of Mark Viner’s odyssey covering his entire solo works illustrates as vividly as any the unfettered imagination and wide-ranging references that inform his music. There are some pages that make you wonder if some illegal substances might have been taken, like the middle section of ‘Ma chère liberté!’, the first of the innocently titled Deux Petites pièces, Op 60, arguably the most bizarre few pages of piano notation until Ornstein or maybe Varèse: if it was not for the precise, meticulous notation you would think it was the work of a two-year-old child randomly thumping the keyboard. Then there are the dizzying digital flights of virtuosity that astonish as much by their concept as their execution. Try the Toccata, Op 75 (marked quasi-prestissimo), a mere 1'48" in length, or the relentless (5'02") semiquavers of Le chemin de fer: call it a toccata, tone poem or perpetuum mobile, it is the earliest example I know of mechanical music and certainly the first musical depiction of a steam engine, published as it was in 1844. If Alkan could play it as Viner does here, no wonder he was the only pianist in front of whom Liszt was hesitant of playing.

Side by side we have the two Alkan masterpieces that are Op 50, Capriccio alla soldatesca and Le tambour bat aux champs, military tone poems that alternate between camaraderie, loss, high spirits, mockery, despair and triumph. Alkan would surely have been writing for the cinema were he around today. There are two premiere recordings: the strange little canonic Pour Monsieur Gurkhaus and ‘Jean qui rit’, which turns out to be a diabolically difficult (to play) take on the brindisi (‘Fin ch’han dal vino’) from Don Giovanni. Elsewhere, there is much to astound and enjoy in Alkan’s delight at presenting opposite and contrary subjects of a far less obliging nature than Schumann’s Eusebius and Florestan.

Last of all in this bran tub of unexpected treasures come the Trois Petites fantaisies, Op 41, further masterpieces described by Mark Viner in his extensive and authoritative booklet as ‘unique in his catalogue for their dry humour, whimsical character and brilliant, explosive energy’. Lovers of transcendent pianism – superbly recorded, by the way – and high-octane bravura need not hesitate, but it is Alkan’s unconstrained flights of fancy that amaze more than anything.