The 1969 Proceedings of the Plenary Session of the European Organization for Research on Treatment of Cancer have been divided between two volumes of a com- pletely different nature. Volume 29, Aseptic Environments and Cancer Treatment, deals not only with the treatment of all types of cancer but also with aplastic treatment of bone marrow and certain other pathological conditions, such as immunological insufficiency, bums etc. Hence the volume will be of interest not only to carcinologists and haematologists but also to paediatricians, surgical units, intensive-care units, hospital administrators and architects and engineers who specialize in hospital design and equipment. Volume 30, Advances in the Treatment of Acute (Blastic) Leukemias, deals with a particular form of cancer and will have a more restricted readership of carcinologists specializing in leukemia and all haematologists. Paris, April 1970 GEORGES MATHE Contents Introduction. G. MATHE. 1 Five Years Experience of the Clinical Use of a Pathogen-Free Isolation Unit. G. MATHE, M. SCHNEIDER, 1. SCHWARZENBERG, J. 1. AMIEL, A. CATTAN, J. R. SCHLUMBERGER, M. HAYAT, F. DE VASSAL, CL. JASMIN, and CL. ROSEN- FELD. With 3 Figures . 3 Protected Environments and the Use of Antibiotics. H. E. M. KAY, J. BYRNE, B. JAMESON, and J. LYNCH . 14 Protected Environment, Prophylactic Antibiotics and Cancer Chemotherapy.