Cage's Sonatas and Interluded are very interesting indeed, John.

Cage was in fact a very great composer. I'm not very interested in his experimental work, although I like his radio work (Roratorio for instance). I have a feeling that the pieces he actually wrote down were his best.

I've also noticed that his pieces for prepared piano always sound very different. I think this has to do with the way the piano is prepared. The performance by Gerard Fremy on ETCETERA for instance, sounds very different from the one Aleck Karis made on BRIDGE. I don't believe the only reason for this is the way these two pianist play. The prepared piano music of Cage always sounds different, rather like the different sound of Mozart being played on a Steinway or on a piano forte.

I have a catalogue edited by Dick Raaijmakers of an exhibition that was held in The Hague more than ten years ago about "open" instruments. In this catalogue there is a chapter on Cage's prepared piano. It quotes from a text by Cage called Composition as Process (1958): "The materials, the piano preparations, were chosen as one chooses shells while walking along a beach." Then follows a long list compiled by Mrs Monika Fürst-Heidtmann, who wrote a book in German about the prepared piano. I will put up this list later on, I don't have enough time now. I will also put up some Sonatas by Cage.

My mistake, the Explore re-issue of the Tilbury recording does have the table of preparations, but you might need a magnifying glass to read it.

http://en.wikipedia.org/wiki/Works_of_John_Cage is also worth a glance.

John, here's the list by Monika Fürst-Heidtmann I told you about:



 

Very good! Gene Carl, the writer of this chapter on Cage, compares the preparing of the piano with the preset of a synthesizer.

from http://blog.spiralcage.com/?p=32 :

"Sonatas and Interludes for Prepared Piano (John Tilbury)

"A single grand piano in the center of the stage lit by a white flood light. John comes out in his trademark black leather jacket and sits at the piano. He looks at the first page of the score and then begins those familiar opening notes of the Sonatas and Interludes. After he plays each section he would stop and turn the page. Then we would again examine the page, putting a gap and some silence between each of the sonatas and interludes. A prepared piano never sounds exactly the same and the preparations can shift and subtly evolve during the course of a performance. Of course some parts will be a bit slower or faster and the sound of the room is always different as well. So this piece, which John has played so many times, was familiar yet different. But it was absolutely sublime and fascinating to watch John play it. He would cross hands often to play treble notes with his left hand and bass with the right, most dramatically in Sonata IVX with the simple melodic phrase being played with the left hand whilst underneath it the right continuously massages a couple of keys. Then the left hand would cross back over and pick up a note or two.

"Gordon Mumma was overheard saying about seeing Tilbury; “I came for the Sonatas and Interludes, I just put up with all the rest.” This was the musical event of the year for me, my favorite pianists playing an amazing piece of Twentieth Century composition in an excellent setting."

John, you really could have found this out with a bit of Googling for "Cage" and "prepared piano", but the origins of his use of preparations lay partly in the influence of Henry Cowell, but mostly in necessity. He was asked to write some music for a dance. He was mainly known for writing music for his percussion ensemble at the time, but there was no room for such an ensemble in the venue, but there was a grand piano, so tried modifying the sound of that piano to create a wide range of timbres somilar to those associated with a percussion group. Later he refined his method, reaching its peak in works like the Sonatas and Interludes and the Book of Music for Two Pianos.

He did invent new instruments, each time he worked out a new set of preparation for a new piece.

http://en.wikipedia.org/wiki/Prepared_piano is pretty reliable.