There are two major differences in concept between this volume and others in the International Histological Classification of Tu mours series. The first of these is the inclusion of more clinical aspects than has usually been the case and the second is a con centration on a more limited range of conditions. There are sev eral reasons for adopting this approach. With regard to both cancer and pre cancer of the oral mucosa, we believe it is impor tant that general pathologists, in whose interests this volume has primarily been written, should be informed of the significance of the clinical...