This document provides an introduction to the theory of complex adaptive systems and living systems. It defines them as systems composed of interacting elements that can adapt to each other's behavior without centralized control. Key properties discussed include holarchic structure from cells to ecosystems, open exchange with the environment, adaptation and self-organization, emergence of new behaviors, and sensitivity to initial conditions. The theory views systems as evolving over time from stability to new dynamic equilibria through bifurcation points in a nonlinear way.