The proposed UCSF Core Center for Patient-centric Mechanistic Phenotyping in Chronic Low Back Pain (UCSF REACH) will be an interdisciplinary consortium of basic and clinical scientists dedicated to understanding and clarifying the biopsychosocial mechanisms of chronic low back pain (cLBP). The goal of UCSF REACH is to define chronic low back pain (cLBP) phenotypes and pain mechanisms that can lead to effective, personalized treatments for patients across the population. A fundamental challenge for improving lives of cLBP patients is that pain can perpetuate and worsen as a result of dynamic interaction among several patient-specific factors. However, the principle factors and their interactions remain obscure because they haven't been rigorously investigated in a single longitudinal cohort. REACH proposes to overcome this obstacle by forming a linkage between researchers who study disease biology, experts who develop advanced investigational tools and methods, scientists who analyze vast archives of clinical data, and practitioners who actively treat patients. UCSF REACH proposes six cores: 1) Administrative Core; 2) Clinical Core; 3) Informatics Core; 4) Bio-behavioral Core; 5) Pathophysiology Core; and 6) Physical Function and Biomechanics Core. These cores will provide support to a single research project that is focused on the challenge of developing validated and adoptable tools that enable comprehensive yet routine clinical assessment and treatment of CLBP patients. REACH will also foster scientific exchange through an Enrichment Program; the curriculum includes seminars featuring local and visiting scientists, an annual full-day retreat with the External Advisory Committee, and half- day symposia with a rotating topic relevant to the biopsychosocial model of cLBP. Another vital component of REACH is its Pilot/Ancillary Studies Program. This provides seed money to leverage REACH clinical data and cores. Overall, the object of REACH is to make optimum use of all available resources to catalyze discovery and translation of novel diagnostics and therapeutics that improve outcomes of cLBP patients.