1. In the 12 week Treatment Phase, we will enroll 320 adults with chronic low back pain(CLBP) from predominately low-income minority communities and compare the effectiveness (co-primary endpoints pain and function) between (1) a standardized protocol of one yoga class per week; (2) a standardized exercise therapy protocol based on an evidence-based clinical guidelines individually delivered by a physical therapist; and (3) an educational book on self-care for CLBP