If there is a single quality that defines the career of German pianist, composer, producer, and painter Joachim Kühn, it is curiosity. His style crisscrosses classical music, avant-jazz, post-bop, modern composition, stride blues, free improvisation, global folk traditions, and even rock. His mercurial approach balances vehemence and sensitivity, imagination, and a fluid sense of dynamics. Kühn left formal classical studies to follow his older brother, clarinetist Rolf Kühn, into jazz. They cut Impressions of New York in 1968, and the following year combined avant-jazz and psy...