Paperback in very good condition. Original brown wrappers. Slight tear to top of spine. Previous owner's blind stamp on cover. Researches on Population Ecology Supplement No. 1, September 1971. Inserted corrigendum and erratum. A study of major existing models for predation and parasitism, and its aim is to evaluate the roles played, or those not played, by these models in helping our insight into the relationships underlying prey-predator and host-parasite interaction systems.