This chapter combines the modelling approaches of Chapters 4 – 7 to investigate how and why species can coexist. For this the chapter presents main arguments and concepts that have been presented in the literature over the past few decades, which include, among others, niche separation, the competition-colonisation trade-off and the intermediate disturbance hypothesis. Modelling examples from the literature that introduce and investigate these concepts are outlined. Some of the models are stochastic, most of them contain spatial structure and all of them, of course, consider individual variability, either through equation-based models or individual-based models. Various models, expecially the more recent ones contain all three features. Species coexistence is one of, or may be even the most, important question analysed in the research fields of (meta) community ecology.