Great pianist that he was, he could not resist the lure of transforming works for other instruments, most famously the Chaconne from Bach's Sonata in D minor for solo violin, BVW1004. This is already a masterpiece that one can soak up again and again without ever exhausting it.
I have a splendid portrait, I guess you'd call it, of the violin score framed on the wall, bigger than A2 size, all flowing curves, which Mrs L got me as a birthday present a couple of years ago, and it never fails to interest passers-by!
Busoni said this in defence of his piano arrangment (probably made in 1891/2): I start from the impression that Bach's conception of the work goes far beyond the limits and means of the violin, so that the instrument he specifies for performance is not adequate [for its realization]. This begs the question of the separation of a 'work' from its performance and possibly undervalues the lyrical qualities of the violin, but I can't escape the nagging feeling that such a sentiment is true of a lot of Bach, which often seems to exceed its instrumentation.
The Busoni arrangement has a special place in my heart, as I first heard it on honeymoon. I next heard it on a lovely walking holiday in the Cotswolds when I bought a CD of Busoni himself playing it (via an 88-fingered piano-roll reader seated on a modern Steinway) from the most fascinating museum in the world (measured in terms of value per square metre), Keith Harding's World of Mechanical Music. This truly is a place worth walking to see, wherever you're starting from.
And now it has a birthday connection, since one of my piano students has a very generous mum, who gave me the score of Busoni's arrangement despite a blanket ban on birthday presents this year! I won't say I've been doing nothing but play it since I turned 30, but...
A great birthday it was, thanks jointly to Mrs L's organising and hosting-gliding on the day and to the great numbers of friends who made the trek (some hundreds of miles) to Cambridge to celebrate with me. The only down-side was that I couldn't spend more time with everyone! There were some Cambridge friends I hadn't seen for 5 years or more. It took a day to recover!