The first edition of Radiation Therapy of Benign Diseases - A Clinical Guide by S.E. Order and S.S. Donaldson grew out of a project supported by the National Academy of Sciences. It represented a unique and significant contribution to the utilization of radiation therapy techniques in the management of benign diseases. It remains a valid observation that low-dose radiation therapy can have significant beneficial effects in the management of benign diseases. The second edition has been expanded and identifies broader major applications for radiation therapy techniques in this very controversial area. It significantly augments the first edition by inclusion of the use of radiotherapy for newer benign diseases, including macu- lar degeneration, vascular restenosis, and other conditions. The authors have succeeded in documenting the current diverse roles of radiati- on therapy in the treatment of benign diseases. This volume represents a significant and important contribution to our armamentarium for the treatment of these diseases.