FOREWORD It is important to record here again that Dr. Copeland and Dr. Geschickter were research fellows in the Surgical Pathological Laboratory of the Johns Hopkins University and Hospital for six months only, ending Jan. 1, 1929. Previous to entering on this investigation on tumors of the bone, they had studied the bone material and published in theArchives of Surgerya comprehensive investigation of multiple myeloma. This work was performed while they were medical residents at the Baltimore City Hospital under the supervision of my colleague, Dr. Boggs, and I should like to record here my appreciation of the aid and opportunities that he gave these two young medical graduates. During these six months every tumor of the bone, benign and malignant, and every example of disease of the bone, were studied comparatively, first microscopically and then in the gross and by roentgen and clinical pictures. To make this