Case exercises are an effective way to increase one's understanding of the appropriate applications of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides). The examples presented here are among the more than seventy cases included in the new edition of The Guides Casebook. The first case involves a 31-year-old woman who experienced acute low back and left leg pain while lifting and twisting at work. Diagnostic evaluation included MRI of the lumbar spine, which showed a herniated nucleus pulposus at L3-4, impinging on the left L4 nerve root. The diagnosis of lumbar radiculopathy was confirmed with electromyography. The AMA Guides, Fourth Edition, awarded 10% whole person impairment; the Fifth Edition awarded 5% (from a recommended range of 5% to 8%); and the Sixth Edition awarded 7%. The second case involves a 26-year-old woman whose stopped car was struck at 5 miles-per-hour in a rear-end collision. She described neck and low back pain but denied radicular symptoms and showed no signs of either neurologic or musculoskeletal impairment; her cervical spine and lumbar spine flexion and extension plain films were normal. Ten months after the accident, she had not returned to work, and consultation with a rheumatologist led to a diagnosis of fibromyalgia. The article discussed evaluation using the fourth, fifth, and sixth editions of the AMA Guides, each of which recommended 0% impairment.