On the South Side of Chicago in the 1960s, African American artists and musicians grappled with new language and forms inspired by the black nationalist turn in the Civil Rights movement. The Freedom Principle, which accompanies an exhibition on the topic at the Museum of Contemporary Art Chicago, traces their history and shows how it continues to inform contemporary artists around the world. The book coincides with the fiftieth anniversary of the founding of the Association for the Advancement of Creative Musicians (AACM), a still-flourishing organization of Chicago musicians who challenge jazz's boundaries. Combining archival materials such as brochures, photographs, sheet music, and record covers with contemporary art work that respond to the 1960s Black Arts Movement, The Freedom Principle explores this tradition of cultural expression from, as one AACM group used to put it, the "ancient to the future." Essays by curators Naomi Beckwith and Dieter Roelstraete, AACM member and historian George Lewis, art historian Rebecca Zorach, and gallerist John Corbett accompany beautiful reproductions of work by artists such as Muhal Richard Abrams, Barbara Jones-Hogu, Cauleen Smith, Rashid Johnson, Nick Cave, and many more. A roundtable conversation features Beckwith, Roelstraete, curator Hamza Walker, current AACM member and cellist Tomeka Reid, and scholar and curator Romi Crawford, with additional comments from poet and scholar Fred Moten. A chronology and curated playlist of AACM-related recordings are also included. The resulting book offers a rich sense of a global movement, with crucial roots in Chicago, driven by a commitment to experimentation, improvisation, collective action, and the pursuit of freedom.