A quite different approach to modelling agents was taken by Singh, who has developed an interesting family of logics for representing intentions, beliefs, knowledge, know-how, and communication in a branching-time framework [Singh, 1991b][Singh and Asher, 1991][Singh, 1991a][Singh, 1990]; these articles are collected and expanded in [Singh, 1994]. Singh's formalism is extremely rich, and considerable effort has been devoted to establishing its properties. However, its complexity prevents a detailed discussion here.