The fourth edition of the AAOS Atlas of Orthoses and Assistive Devices (Elsevier, 2008, $199) hit Amazon.com and brick-and-mortar bookshelves on June 20, according to Elsevier. In conjunction with the American Association of Orthopaedic Surgeons (AAOS), authors John D. Hsu, MD; John Michael, MEd, CPO, FISPO, FAAOP; and John Fisk, MD have significantly revised the new 672-page edition and added a two-color format to improve information retainability. According to the Elsevier website, the atlas will contain new chapters on cranial orthoses and orthoses for persons with post-polio syndromes and post-polio paralysis. Each chapter will also include sidebars with personal perspectives and tips from well-known physiatrists. Existing, revised chapters cover orthotic prescription, strength and materials, normal and pathologic gait, and biomechanics of the spine, upper limb, hand, and lower limb. The chapters on spinal and upper- and lower-limb orthoses include new evidence-based recommendations for prescription. Elsevier also notes that the new edition contains "information about the specific science behind the construction of orthoses." Hsu is chairman of the department of surgery (retired) and chief of orthopedics at Rancho Los Amigos National Rehabilitation Center in Downey, California. Michael is president and CEO of CPO Services Inc., Portage, Indiana, and a contributing editor at the Journal of Prosthetics and Orthotics (JPO). Fisk is a professor in the department of orthopedic surgery and rehabilitation at Southern Illinois University School of Medicine in Springfield, Illinois.