IntroductionConsumer-resource systems can be regarded as any system in which a population of organisms exploits either an energy flux, a detritus or nutrient pool, or another population. This definition then includes plants growing in sunlight, parasites growing in or on hosts, predators exploiting prey, herbivores grazing or browsing on plants, and even humans harvesting trees, fish or game. For such a vast array of systems, no single best paradigm exists for modelling the dynamics of the populations under consideration.Here I will focus on two paradigms: a discrete-time paradigm that is suitable for modelling populations with nonoverlapping generations and a continuous-time paradigm that is suitable for modelling the flow of biomass from the resource to the consumer, and its conversion from resource mass (biomass, nutrients, or energy) into consumer mass. I will also consider the extension of the discrete-time paradigm to include overlapping generations (age structure) and the application of the models to resource management problems.The discrete-time models fall within the class of iterative maps (7.1)where, for the systems considered here, the elements of the vector x t = (x 1t , x 2t , . . ., x nt )¢ (¢denotes the transpose of a vector) typically represent the densities of individuals in n biological populations at time t = 0, 1, 2, 3, . . . or the densities of individuals in n classes (e.g., age or size) of one population at time t, or even some combination of several populations each with several classes of individuals. The continuous-time models fall within the class of vector differential equation systemswhere, for the systems considered here, the elements of the vector x(t) = (x 1 (t), x 2 (t), . . ., x n (t))¢ typically represent the biomass densities of n interacting biological populations at time d d x x t = ( ) y , x x t t t + = ( ) = 1 0 1 2 y , , , . . .