This book has become necessary as a consequence of the rapid expansion of the surgical procedures and implants available for spinal surgery within the "AO Group". We have not attempted to write an in-depth book on spinal surgery, but one which will help the surgeon in the use of AO concepts and implants. We con­ sider the practical courses held all over the world essential for the teaching of sound techniques so that technical complications and poor results can be avoid­ ed for both the surgeon and, in particular the patient. This book is a practical manual and an outline of what is taught in the courses. It is intended to help the young spinal surgeon to understand