Active Walk (AW) is a paradigm for self-organization and pattern formation in simple and complex systems, originated by Lui Lam in 1992. In an active walk, the walker (an agent) changes the deformable landscape as it walks and is influenced by the changed landscape in choosing its next step. Active walk models have been applied successfully to various biological, chemical and physical systems from the natural sciences, and to economics and many other systems from the social sciences. More recently, it has been used to model human history. The first AW paper was published in 1992. In the two reviews published in International Journal of Bifurcation and Chaos (World Scientific, 2005 and 2006), the history, basic concepts, formulation, theories, applications in nonliving and living systems, new developments and open problems of active walk are summarized and discussed.