the world health organization (who) has launched a new project called the world health organization classification of tumors, continuing the international histological classification of tumors. this project aims to standardize tumor classification and provide histopathologic criteria, along with information on molecular genetics, which are increasingly important in cancer typing and predicting treatment response and clinical outcomes. the first volume, entitled pathology and genetics of tumors of the nervous system, has been published and is available from iarc press. it was the result of a collaborative effort by 106 neuropathologists and geneticists from 21 countries, meeting at the international agency for research on cancer (iarc) in july 1999. the second volume, covering tumors of the digestive system, is currently in preparation and will be the result of an international working group meeting at iarc in november 1999. rapid publication is essential due to the fast pace of progress, especially in tumor genetics. the goal is to cover all tumor sites within five years. the project aims to make the new who "blue books" the standard reference for tumor classification worldwide and a reliable basis for communication among pathologists, clinicians, and the basic cancer research community. the first volume was edited by paul kleihues and webster k. cavenee.the world health organization (who) has launched a new project called the world health organization classification of tumors, continuing the international histological classification of tumors. this project aims to standardize tumor classification and provide histopathologic criteria, along with information on molecular genetics, which are increasingly important in cancer typing and predicting treatment response and clinical outcomes. the first volume, entitled pathology and genetics of tumors of the nervous system, has been published and is available from iarc press. it was the result of a collaborative effort by 106 neuropathologists and geneticists from 21 countries, meeting at the international agency for research on cancer (iarc) in july 1999. the second volume, covering tumors of the digestive system, is currently in preparation and will be the result of an international working group meeting at iarc in november 1999. rapid publication is essential due to the fast pace of progress, especially in tumor genetics. the goal is to cover all tumor sites within five years. the project aims to make the new who "blue books" the standard reference for tumor classification worldwide and a reliable basis for communication among pathologists, clinicians, and the basic cancer research community. the first volume was edited by paul kleihues and webster k. cavenee.