Predator–prey models have a long history in mathematical modelling of ecosystem dynamics and evolution. In this chapter an introduction to the methodology of mathematical modelling is given, with emphasis on microbial predator–prey systems, followed by a description of variants of the basic two-species system. Then the two-species system is extended to incorporate effects such as predator satiation and prey escape strategies, after which multi-species effects, including alternative prey, protector species and decoy effects, are discussed. Simulations are used to discuss the effect of several model parameters