Chapter 1 presented the basic ideas behind the theory, which are analyzed in some detail. Chapter 2 described the heuristic models of several relevant combinatory systems in the context of the five typical classes. Chapter 3 developed the Theory of Combinatory Automata, which present models for simulating the dynamics of combinatory systems. This final chapter considers the “explanatory power” of Combinatory Systems Theory for understanding the logic of collective dynamics, understood as a unitary (macro) object of observation, even though collectivities are composed of a “plurality” of individual entities capable of autonomous (micro) behavior (agents, individuals, operators, etc.). The chapter attempts to answer three questions: Are combinatory systems “systems” in the true sense of the term? Why is this theory able to explain so many and so varied a number of phenomena, even though it is based on a very simple modus operandi? Are combinatory systems different than complex systems?