For most of us in the West classical music calls up visions of men in tuxedos and women in long gowns playing highly formalized and rigidly controlled music. This is the last type of music we'd ever associate with any sort of improvisation as the musicians are there to serve the wishes of the composer as interpreted by the conductor. Unless they're soloists of very high standing they have little or no say in how the music sounds and what it expresses.
So it might come as a bit of shock to find out that the traditions surrounding classical music in other cultures actually encourage improvisation. For, while in countries like India there are certain formal patterns of structure adhered to, within the form there is plenty of room for the musician to interpret the music. The performances of music is considered a personal and spiritual journey, a means of expressing a connection to the gods, so it can't help but change from individual to individual. India is not unique in having this kind of musical tradition, and considering the cross-pollination of culture between the two countries down through history, it's not surprising to find a similar tradition has existed in Iran since the twelfth century.
Persian classical music, like many others where there was originally nothing committed to paper, involves a long and involved training period for anybody wishing to perform it. First of all a student has to memorize a canonic repertoire known as radif (literally translated as "order") comprised of over 200 modal pieces of music known as gushehs. These gushehs are grouped together as progressions of modally related pieces into twelve distinct dastgah (systems). Once a musician has memorized all the gushehs individually and collectively in their respective dastgah, they are ready to begin creating. Unlike in the West where we have specific pieces of music to perform, the radif is not something that is actually performed as an individual piece of music, but instead serves as the starting point for creative improvisation.
Of course in listening to music the theory behind it usually flies out the window as you get swept up in the sounds and emotions being generated by the artist in question. Such is the case with I Will Not Stand Alone the latest release from Kayhan Kalhor on World Village Music. The recording features Kalhor playing a variation on the traditional Middle Eastern four-stringed bowed instrument, the kamancheh (called a shah kaman) accompanied by Ali Bahrami Fard on a hammered, dulcimer-type instrument known as a bass santor. If you have any thoughts that the conditions described above for the creation and playing of music were restrictive they will be quickly dispelled as you listen to what these two men are able to generate between them.