Chronic low-back pain affects the physical function and quality of life of many individuals and constitutes one of the largest medical and socioeconomic problems today. Fusion of the spine has become a common approach to treatment of back disorders and in particular for degenerative diseases associated with back pain. Moreover, complex fusion procedures with potentially more complications have been introduced in hope of attaining a better outcome. Also a wide variety of spinal motion preservation techniques- most notably the disc prosthesis are being employed because of their theoretical advantage in reducing the risk for long-term complications. However, the evidence in favour of more sophisticated approaches than the standard posterolateral fusion is still weak and fusion of the degenerative lumbar spine have remained controversial. This book summarizes causes and treatments of chronic low back pain and especially in spondylolisthesis. It deals with this huge problem and among much else gives conclusions on treatment by fusion. The book should be most useful for professionals dealing with chronic low-back pain as well as interested individuals maybe suffering from this condition.