Imagine a missing link between Scarlatti and Beethoven, a composer whose outpouring of keyboard sonatas blends the crystalline clarity of the galant with the tone and textures of Romantic pianism. Miraculously, such a composer existed. Yet Muzio Clementi (1752–1832), acknowledged in his time as a peer of Haydn and Mozart, has been air-brushed out of the Classical canon like a victim of a Stalinist purge (one thinks of Trotsky in that famously doctored photograph of Lenin). Mozart, Clementi's nemesis, dispatched him to the gulag of historical footnotes with the famous epitaph of ‘mechanicus without a kreuzer's worth of taste and feeling’ (after their 1781 piano contest). In Britain, Clementi's adopted country since the age of 14, his status was catastrophically diminished by the perennial use by the Associated Board of his op. 36 sonatinas for their grade exams: cute little pedagogical war-ponies, but as little indicative of Clementi's genius as Beethoven's over-familiar 1792 Sonatina in G major (Anh. 5, no. 2) would be of the ‘Waldstein’. In music history, unlike politics, rehabilitation can never come too late. Howard Shelley's complete Clementi cycle, of which the first three double-disk volumes are reviewed here, can be hailed as an event of great importance in this regard. To be sure, Clementi box sets have appeared before, and Naxos (perhaps as a budget-price spoiler) are themselves undertaking a Clementi series in parallel with Hyperion. Nevertheless, I would venture that the Shelley cycle, on the evidence so far, will have no peer. It is a triumph, and no Classical-music lover should be without it. Shelley's playing may not have the virtuosity of the Russian Clementi advocates (I'm thinking here chiefly of Horowitz, and in recent times of Demidenko). But to throw off Clementi sonatas as pyrotechnic bon-bons is to fall into Mozart's ‘mechanicus’ trap. What Shelley brings to the table is sheer poetic sensibility and a sense of Clementi's craftsmanship, qualities which prefigure a later, historically luckier, composer whose own confinement to the piano idiom hasn't compromised his position in the canon at all: Chopin. I will predict that Clementi's rehabilitation will follow in the train of our rediscovery of Handelian opera, and will parallel the enterprising Naxos/Artaria eighteenth-century-symphony project, which has brought to our attention a wealth of wonderful Galant unknowns (Beck, Kraus, Stamitz et al.). Through happy coincidence, the musicological path to the Hyperion/Shelley project was recently laid by Anselm Gerhard's 2002 monograph (London und der klassizismus in der Musik: Die Idee der ‘absoluten Musik’ und Muzio Clementis Klavierwerke), which proposed the audacious, if occasionally tendentious, thesis that Clementi actually invented the Classical Style, and thus not Haydn or Mozart. Suffice it to say, then, that in giving these works our attention, we are not indulging an antiquarian taste for historical footnotes, but are opening ourselves up to masterworks of the very highest calibre. This is music which will give you immense pleasure.

Listeners might well begin their journey at the end of volume 1 with the Sonata in A flat major, WO13, the very earliest work included in the series, which the 13-year-old composer wrote in Rome in 1765, just before his departure. With its thin melody plus accompaniment texture, the sonata is an able exemplar of the kind of idiom practised by contemporary Italian keyboard composers such as Baldassare Galuppi and Domenico Alberti. Disc 1 of this volume, comprising the opp. 1 and 2 sets, illustrate Clementi's so-called ‘virtuosic’ phase, including op. 2 no. 2 in C major, with its notorious octave passages. Although marked ‘Presto’, Shelley doesn't take it particularly fast, thus consciously fulfilling Mozart's complaint that ‘[Clementi] writes Presto over a sonata or even Prestissimo and Alla breve, and plays it himself Allegro in 4/4 time. I know this is the case, for I have heard him do so.’Footnote 1 To be perfectly fair, Mozart's insults are somewhat warranted, since much of Disc 1 sounds empty and vapid, if nicely played. Would that Mozart had heard the string of sonatas Clementi composed from 1782 onwards, throughout his European tour, when he seemed to soak up the culture and grow as an artist. The op. 7 sonatas, which begin Disc 2, are written barely a year after the confrontation with Mozart, yet mark a quantum leap in quality. With no. 1 in E flat, the hallmarks of Clementi's mature style are in place: an architectural firmness in the sonata-form first movement, unfolded through Clementi's quintessentially lyrical feeling for line which Gerhardt christens ‘Cantabile’; a poetic chiaroscuro in the Mesto slow movement, suffused with a poetic melancholy suggestive of the ‘picturesque’ aesthetics of contemporary English landscape gardening;Footnote 2 the elfin, quicksilver charm of the Allegretto spiritioso finale. Shelley delivers all three movements in a convincingly oratorical, quasi-vocal style, just this side of melodrama. The mercurial shifts in tone, between extremes of the earnest and the skittish, epitomize the Sentimentalist aesthetics of the time (like the novels of Richardson earlier in the century); it takes a rare artist to make such potentially queasy displays palatable to the modern sensibility, and Shelley carries it off. Here and there he hams it up, as in the Adagio of op. 13 no. 4, but this particular work invites it: here we find that first inkling of portentousness which would overtake Clementi's slow movements in his later career, throughout the 1800s. Yet that is the exception which proves the rule: in general, where Clementi's tone is authentic, the music absorbs all the expressive intensity that Shelley pours into it. This is demonstrably the case in the first masterpiece of the cycle, the celebrated Sonata in G minor, op. 7 no. 3. With Haydn's early C minor sonata in the background, the piece also points firmly towards Beethoven. Clementi's dramatic scenario in the Adagio Cantabile would be adopted in many of Beethoven's slow movements (see the ‘Waldstein’), where a muted introduction prepares a melodic utterance of stentorian vocal immediacy. Slow movements are the glory of this phase of Clementi's career. The emotion is dark and heartfelt, expressed through dramatic contrasts of texture and dynamics. Shelley's rhetoric turns on a penny, scarcely putting a foot wrong. Not a ‘flashy’ pianist by any means, he is measured and thoughtful, though never pedestrian.

The quality pales somewhat in the uneven first disk of Volume 2, whose highlight (for me) was the breathless Allegro assai finale of op. 10 no. 3 in B flat. Both massive yet fleet-footed, fast yet lyrical, this sounds like nothing by Haydn or Mozart, whose finales cleave instead to the world of the dance. The essence of Clementi's personality here is a paradoxical allegro/cantabile hybrid (lyric, by definition, would seem to be slow, not Allegro). There is a confident play with sound masses here, but without periodicity of phrasing. Phrase repetition for Clementi is contiguous or cell-like – a technique he learnt from Scarlatti. What holds the grand blocks together is his ineffable feeling for line; in this respect as in so many others, Beethoven was Clementi's attentive student. In Shelley's hands, the effect is both precisely detailed and thrilling. With the four great op. 12 sonatas, the quality in the second disc is more sustained. Clementi arguably only ‘cracked’ sonata form with the first of the set in B flat. The Presto first movement (played – like all the other ‘Prestos’ – rather moderately fast by Shelley) convincingly integrates Clementi's favourite textural pasaggi into the sonata drama. Shelley brings Clementi's colour schemes vividly to life, although sometimes to the point of mannerism, as with his frequent trick of retreating to a poetic hush all the better to bring out a vibrant middle-register voice, or a penetrating bass note. It should be pointed out – and this is only a partial criticism – that many of Shelley's dynamics are ad libitum and don't correspond to the early Clementi editions. Certainly, Shelley's dynamic range is much, much, more nuanced and variegated than other Clementi interpreters in the market. It is possible, nonetheless, that his level of timbral differentiation is too fussy; contemporary performance practice made a virtue out of more block-like, broader, contrasts of piano and forte. Compared to the earlier slow movements, the emotional range of op. 12 is more restrained, tapping a neo-Classical vein of nobility suggestive of David's Roman paintings. The finale of op. 12 no. 2 in E flat is one of the best things in the series. The magic is achieved through tricks of register and texture. On the basis of deftly planted deep notes, Clementi floats a meringue of runs and flourishes, rounded out by expressive caesuras. Shelley is not afraid to push rubato to the maximum in the service of articulating these broad textural blocks, bending time in ways certainly licensed by eighteenth- and early nineteenth-century performance manuals (from C.P.E. Bach to Czerny). Stylistically, this wonderful finale affords an object lesson in Clementi's debt to, as much as leave-taking of, Haydn. The rondo theme is an affectionate parody of the finale of Haydn's sonata in the same key. Yet it is quickly overshadowed by a noble, robust, even ‘Beethovenian’ melody which breaks through the episodic passages, and the development takes us into a very different, much darker, world. How strange, then, that the piece holds together, despite the subsequent refrains jettisoning this ‘Beethovenian’ material. The episodes shouldn't fit, but they do, and the overall effect is seamless and weightless. In Clementi's circuitous, eccentric rondo forms, it is the episodes between the refrains which take the journey inwards. Linking these contrasts, Shelley is adept in an art of textural modulation, all framed with judicious caesuras, and dying falls. It is no accident that Leon Plantinga, author of the informative programme booklets, is also a Schumann scholar. Working at either end of the historical watershed, each composer was in his own way a ‘muscular sentimentalist’.

Volume 3 contains two sonatas which epitomize the extremes of Clementi's style. Op. 13 no. 6 in F minor, an astonishing work which may be the most familiar of all his sonatas, does remarkable things with unisono and octave textures – no longer in the service of virtuosity but of poetry. Shelley's Romantic freedom is justified; there is a consanguinity here with Chopin's B flat minor sonata, in which Schumann heard ‘the wind howling around the gravestones’:Footnote 3 the textural boldness of Chopin's unisono finale would not have been possible without the discoveries of the English Pianoforte School, especially Clementi. At the other extreme, op. 24 no. 1 in F major ends with an Air with variations: Allegretto vivace. Like the finale of op. 12 no. 1 in B flat major (volume 2), the wonderful Lindor with Variations, this movement indulges that suave urbanity which so strongly impressed the early Beethoven. Clementi was a great lyricist, and Shelley does justice to the luscious pyramid of confectionary the composer mounts on the theme through the successive variations. What can I say? These captivating works are fixtures on my iPod, and Clementi's tunes have soundtracked my life for a couple of years. I couldn't recommend this set of discs more urgently. I look forward with equal enthusiasm to the future instalments of a project which will be as significant as Hyperion's pioneering Schubert Lieder project.