In middle age some men take up marathon running. Others climb the Matterhorn or buy a red sports car. Alan Rusbridger, editor-in-chief of the Guardian, decides to master Chopin's First Ballade, Op 23. Following an epiphany during a French summer course, Rusbridger gives himself a year to learn this fiercely demanding work, later extending his self-imposed deadline when at various points Julian Assange and the families Gaddafi and Murdoch eat into his practice schedule.

This is a journal of that year: part piano diary, part day-by-day breakdown of what a 21st-century editor actually does. The result is a unique melange of political and musical reportage, meditations on music-making deftly interwoven with reflections on the ever-changing newspaper industry. The frenetic pace of Rusbridger's working life contrasts starkly with the tortoise-like speed of his pianistic progress, documented through detailed, self-flagellating metronome marks. WikiLeaks kicks into touch the problems of fingering and hand position; the hacking of Milly Dowler's phone puts paid to memorising. Rusbridger's account of the volatile, dislikable Assange is particularly compelling, and the ebb and flow of WikiLeaks runs as a strong contrapuntal theme throughout the book. What's more, readers can now identify a story of this magnitude as a marmalade dropper, aka, in tabloid circles, a Fuck Me Doris.

To a professional pianist the practice diary induces exquisite agony, as the Titanic inches in slow motion towards the iceberg of performance. Some might consider the level of detail obsessive. Should this octave be played with the fifth finger or the fourth? Might the third, even, be considered? One could argue that if Rusbridger has to ask these questions, he shouldn't be tackling the Ballade in the first place; but as he cheerfully fesses up to hubris early on, all can be forgiven. An Amateur Against the Impossible is the book's subtitle, and for good reason. Despite an abundance of piano teachers, there is an irresistible urge to shout out advice. Mate, learn some other pieces! Dude, harness your muscle memory! At which point up pops a handy neurologist, explaining that muscle memory doesn't exist: it's actually procedural memory, and most fascinating it is, too.

But then, procedure here is all, the end result less important than the journey. In the course of his piano year, Rusbridger ducks off-piste at regular intervals to interview luminary pianists. Daniel Barenboim puffs a large cigar at Claridge's; Murray Perahia proffers chocolate cake in St John's Wood; Charles Rosen, painfully soon before his death, opens the door of his Manhattan apartment in pyjamas. Alfred Brendel, a reluctant Chopinist, looks on magisterially. Richard Goode, Emanuel Ax, Noriko Ogawa and Stephen Hough chip in too. Almost all learned the Ballade on entering puberty. "It seems to be a piece everyone wants to try as a teenager," Rusbridger punts out at Barenboim. "Yeah," comes the voice of experience, "and then as an adult mostly avoids it!" All shed precious light on the Ballade, on Chopin, on performance. Ronan O'Hora is particularly insightful on how the piece invites hysteria in performance, drawing a parallel in Chopin's output with Elektra in Strauss's.

These contributions are central to the book's success. The author meanwhile illuminates not only print media in this digital age but also the changing role of music within it; much thought is given to the complementary roles of professional and amateur, of solo performance and chamber music played with friends. Two images endure: the perpetually overworked Rusbridger discussing Chopin manga cartoon books with "Suzie K", a young Japanese pianist befriended on the Ballade Twitter feed; and an exhausted Rusbridger picking out fragments of his beloved Chopin in the restaurant of a sinister, deserted Tripoli hotel during a rescue mission to Libya, unsure how he's to get back to Blighty.

The book is handsomely produced, rich in both musical and photographic illustrations. At the end, delightfully, sits Rusbridger's own annotated score, complete with thoughts from his galaxy of star pianists. A couple of minor quibbles. Some of the musical spelling-out struck me as inconsistent. If you have enough technical know-how to enjoy the annotated score and make it through several pages of detailed harmonic analysis, you may already know that the classical tradition is represented by Haydn, Beethoven and Schubert. When towards the end Condoleezza Rice appears, I began to suffer from famous friend fatigue. Yes, Ms Rice's high-achieving, piano-playing, ice-skating childhood was indeed remarkable. When it comes to commenting on Chopin, though, I'll stick to Hough and O'Hora.

Finally, after more lessons from more teachers, the day of the climactic performance arrives. We never discover if Rusbridger heeds Boris Berezovsky's pragmatic advice: "Pedal helps to cover up mistakes and other stuff  so just put it on and enjoy." Enjoyment may not be the word, but Rusbridger emerges unscathed and quietly triumphant, older and wiser. The Matterhorn has been scaled, his epiphany rewarded. Mrs R's emotions at never having to hear this piece again are not recorded. Rusbridger's year at the piano makes an irrefutable case for the physical, spiritual and therapeutic benefits of playing. He also emerges with a dent in his pocket: a good piano, it turns out, costs just as much as a red sports car. It also goes further.

Iain Burnside is a pianist, broadcaster and writer. His new play, Journeying Boys, opens at the Royal College of Music on 8 February