of the interaction and relationship of both systems is chal­ In this volume, aspects of neoplastic spread, already elu­ cidated in Volumes I-IV of this series, are considered lenging indeed. against a broad biological background. The mammalian The volume also reviews environmental oncology and species-specific aspects of environmental chain reactions. It orders constituting the logical framework for man as focal point of a comparative oncology are reviewed. Selected is apparent that the environment plays a significant role in examples of neoplastic progression in various taxonomic the development of neoplasms. Neoplasms among the spe­ units are provided, beginning with the opposite pole of ci es have become much more common as a result of man's taxonomic development, the vascular plants, where no impact on the environment. The latter chapters present a metastatis of malignant neoplasms occur. Among in­ brief review of geologic and technologic and cuItural vertebrates, vertebrates, and vascular plants, Iining mem­ changes, and the implications of species-specific cancer pro­ branes (epithelia) exhibit the highest degree of comparabil­ gression. The remainder of this section outlines a number of ity. Metastases also occur, but more rarely, in invertebrates, selected chain reactions leading to neoplastic development and are discussed as they are found in the nonmammalian in certain members of these chains. A discussion of the vertebrates: in fish, amphibians, reptiles, and birds. Diseases storage of chemical carcinogens in plants and their interac­ ofthe leukemia (Ieucosis)-Iymphoma complex are present in tion with other causes of neoplastic growth is also included.