Whereas algebras are used to model abstract data types, coalgebras are used to model dynamic, state based systems.

This is a text for dedicated undergraduates with no previous experience in modal logic. The book should prepare people for reading advanced texts in modal logic, such as Goldblatt, Chellas, Hughes and Cresswell, and van Benthem.

Contents: Basic Concepts; Classical SL; Absolute Modal Logic - System L; Relative Modal Logic - System K; Systems Between K and L; Modal Predicate Logic; General First-Order Logic; First-Order Modal Logic.

This Handbook documents the current state of modal logic, a lively area of logical research which was born in philosophy, but which has since made its way into mathematics, linguistics, computer science, AI, and even economic game theory.

The skeleton of this narrative nonfiction book is a science fiction story without the usual mangling of physics.