Like its west Asian and Indian counterparts, Persian music is characterized by microtonal scales, a modal improvisational approach, and a free rhythmic sensibility. A core Iranian classical instrument is the kamancheh, a spike fiddle or bowed lute with a distinctive high-pitched tone, held upright and played in seated position. Kayhan Kalhor, a Tehran native of Kurdish descent, took up the kamancheh at age seven, and achieved national prominence following his invitation to join Iran's National Orchestra of Radio and Television at age 13, shortly before the revolution. Kalhor also studied Western classical forms and apprenticed with fellow Kurd Ali Akbar Moradi on the tanbur (a plucked, long-neck lute associated with Sufi mysticism). In The Mirror Of The Sky reunites these two masters after a two-decade hiatus. With tombak (goblet drum) backing, Kalhar and Moradi (also an evocative singer) improvise in the modes of Kurdistan, a territory covering western Iran and parts of Iraq, Syria, Turkey and the former USSR. This music taps the deep spiritual underpinnings that may be the region's best hope.