A methodology for describing fissile fuel production and fertile fuel utilization is provided, based on lumped reactor physics parameters, the establishment of symbiotic relationships between breeders and converters, and the use of material stockpile inventories. The system is taken to consist of a general breeder reactor coupled to a fission converter reactor and fuel reprocessing-fabrication plant. The consumption of electricity by the reactors and processing plant as well as the production by the system is explicitly included. The synergetics of fast-fission breeders, symbiotic fusion, hybrid fusion and spallation breeders are then investigated. The fissile and fertile inventories and power output are calculated over the system lifetime for a specific breeder power. The effects on the system inventories of varying breeder thermal power are also examined. No single breeder system is shown to consistently outperform the others.