<qa>  How many subjects will be recruited from among individuals entering treatment for chronic low back pain?Forty 40 subjects will be recruited from among individuals entering treatment for chronic low back pain at outpatient rehabilitation clinics in the Boston area. Following baseline measures, subjects will be randomized with equal probability 5050 to usual care alone versus usual care plus ten sessions of SI. SI treatment will be provided by qualified SI therapists at their private practice offices. They will be supervised on a monthly basis by a co-investigator with extensive prior experience in the clinical practice of SI. 