Improvisation is not just for jazz and for the blues. Check out the amazing artistry of Pandit Ravi Shankar, a renowned Classical Indian musician. I am no expert in the scales employed in Hindustani (Northern India) classical music, but I know there is a variety from which to choose. This man is an incredible improviser and innovator! He's using a scale, a set of pitches, to create this music. It requires knowledge and training, but more importantly, courage to creatively express with that knowledge.