> This idea \[that modal operators perform quantification without making use of explicit variables and binding], when expressed mathematically, has turned out to be the most significant milestone in the history of modal logic. ## References * Blackburn, van Benthem, Wolter, Handbook of modal logic, Elsevier, 2007. For special chapters and their authors see below in "Contributors. * Carnielli, Pizzi, Modalities and Multimodalities, Springer, 2008 ## Contributors * Yde Venema, [website](http://staff.science.uva.nl/~yde/): algebraic- and coalgebraic aspects of modal logic. e.g [[algebraic- and coalgebraic semantics of modal logic|§6 in the "handbook"]] starting at p.331 in this book without a (global) list of contents. * Blackburn, van Bentham, Modal logic: A semantic perspective, "handbook" §1 * Valentin Goranko and Martin Otto. "handbook" §5 Model theory of modal logic. * Bradfield, Stirling, "handbook" §12 Modal $\mu$-calculi * Sergei Artemov, "handbook" §16 Modal logic in mathematics. modal logics of proof, logics of space and dynamic systems, modal logics in set theory. * Van der Hoek, Pauly, "handbook" §20 Modal logic for games and information. Game theory.