The book reports on cutting-edge Artificial Intelligence (AI) theories and methods aimed at the control and coordination of agents acting and moving in a dynamic environment. It covers a wide range of topics relating to: autonomous navigation, localization and mapping; mobile and social robots; multiagent systems; human-robot interaction; perception systems; and deep-learning techniques applied to the robotics. Based on the 21st edition of the International Workshop of Physical Agents (WAF 2020), held virtually on November 19-20, 2020, from Alcala de Henares, Madrid, Spain, this book offers a snapshot of the state-of-the-art in the field of physical agents, with a special emphasis on novel AI techniques in perception, navigation and human robot interaction for autonomous systems.