thanks, could you also offer your own god-like wisdom on this matter? 
particularly regarding what cziffra does - the multi-technical extravaganza 
I find difficult to express in writing the principles and ideas relating to improvisation. Being a mediocre improviser myself, I am not sure I can speak about it with any authority. Interestingly enough I have taught people to improvise who now can improvise far better than I can.

I hope Ted reads this thread and gives some input because he has some of the most interesting and thought-provoking posts in these matters.
So here are some provisional thoughts on the subject, in no logical order.
1. I recently read the autobiography of American architect Frank Lloyd Wright. One looks at the Guggenhein museum in NY, and we are amazed at a how such a building was built. There are some pictures in the book showing the several stages. And for a long time the building site looked terrible. What a mess! A big hole in the ground, materials scattered everywhere, mud, a horribly looking structure. And yet, once the building was ready and landscaped, what a marvel. We look and listen at accomplished improvisers like Cziffra, Keith Jarret or Egberto Gismonti, and we often forget that we are looking at the finished building, decorated and landscaped. But once upon a time, they too were a mess of a building site. When we attempt our first steps in improvisation, we compare our messy building site with a finished, landscaped top architectural building and we feel frustrated and depressed. But are we doing a fair comparison? To keep going with the architectural analogy, Lloyd Wright had a plan. He was not building a shack.. He was building – in his vision – the most amazing art museum in the world. The whole world may have disagreed, but he was convinced of the worth of his project. So, when we plan to become improvisers, what is our project? A modest hut, or the most amazing building in the world? In order to improvise like Cziffra (and I do not mean here in his style, but with his flamboyance), one needs the same arrogance and supreme self-confidence. Yes, right now the building site looks like s**t, but wait when the building is ready! This is a huge psychological block that no amount of practice or instruction or theoretical knowledge can overcome. If your project is a shack, you will never end up with a Guggenheim.
2. Classical performers, raised on a diet of respect to the minutiae of score directions and respect to the composer’s intentions are not the best candidates for improvisation. In my opinion the most important principle when improvising is that
nothing you do is wrong. Yet this is a very difficult mental wall to climb. I have seen many students developing some wonderful sounds, and suddenly they stop because somehow they believe they made a “mistake”. Somehow the sound they produced at the piano did not correspond to the sound they had in their minds. To have a sound in your mind is a very important strategy for a classical musician (if you hear it clear enough the fingers will comply), but in improvisation it automatically sets you up for failure. I would suggest that a much better approach is not to have any sound at all in mind, and simply, well, improvise! Rather than determining where the music must go beforehand and controlling its movement – a perfectly valid approach when performing music written by others – when improvising one should be very curious to see
where the music is going to take us. My instruction to students with this particular kind of mental block is simple: If you hit what to you seems like a wrong note, repeat it three or four times. So it is no longer a mistake but something you are now doing on purpose, and that will lead your improvisation in a new direction. To me the process of improvisation (both mental and physical) is in many ways similar to the process of automatic writing. You do not know what you are writing, you just write, and at the end you read it and you may be very surprised that rather than it all being a load of random ramblings, there is there a coherent and many times uncannily informative text with information you did not know you had.
3. Improvisation may be a misnomer. I have watched Jacques Loussier doing jazz style improvisation on Bach pieces on many different occasions. And it was not different every time. In fact, he always did the same improvisation to the same pieces. I get the gnawing suspicion that a lot of improvisations are carefully and exhaustively rehearsed.
4. As I look at top improvisers going about their business, the common factor that stands out for me, is how much they are immersed in it. How much they are enjoying it. They might as well be in the privacy of their own home. The audience does not exist, and any thought of showing off is clearly not in their minds: They are as transported by the music they are creating as is the audience.
5. One cannot improvise with one’s consciousness, with one’s awareness. Improvisation is the job of the unconscious. The only role allowed to consciousness and awareness it the role of admiring and appreciative audience. Any attempt from the part of this audience to join in the music making is bound to end up in disaster, and it is going to be as welcome by the performer (the unconscious) as Andras Schiff would welcome a spontaneous rhythmic clapping from the audience accompanying his rendition of Bach Giga in Partita I.
6. From the above, it seems to follow that improvisation requires a certain specific inner state, a definite place in our minds. Once we are firmly established in this special place, the outward form of our improvisation will be a consequence of the repertory of techniques/musical idioms that are at the disposal of our unconscious (This is of course the bit where books, teachers and lessons have their place – they may supply us with this repertory). Hence the very different improvisations of Cziffra and Jarret: They have different unconscious minds. If one wants to improvise like Cziffra, one must program one’s unconscious with the same material. The difficulty of this task explains the uniqueness of Cziffra’s (or anyone else’s) improvisation. And of course, besides the question of difficulty (or possibility / impossibility) there is the question of
desirability. Even if it was possible to build an unconscious like Cziffra’s, would it be desirable?

Best wishes,
Bernhard.