in the late 1950s and early 1960s seminal works on the logic of knowledge and belief were published by notably von wright and hintikka. epistemic and doxastic logics have since then grown into mature disciplines enjoying many important applications in philosophy, computer science, game theory, economics and linguistics to mention but a few fields. the aim of this thematically unified anthology is to track the history of epistemic logic, to consider some important applications of these logics of knowledge and belief in a variety of fields, and finally to discuss future directions of research with particular emphasis on active agenthood and multi-modal systems. knowledge contributors include h. van ditmarsch, r. fagin, j. halpern, j. hintikka, w. van der hoek, b. kooi, w. lenzen, y. moses, h. rott, j. sowa, m. vardi and r. wójcicki. knowledge contributors is accessible to researchers as well as graduate students in philosophy, computer science, game theory, economics and related disciplines utilizing the means and methods of epistemic logic.