Lloyd Humberstone

This text aims to convey some of the interest and charm of modal logic, and to put a reader new to the subject in a position to have an informed opinion as to its applicability to each of several areas of philosophical concern (belief, knowledge, obligation,...) in which the merits of a "modal approach" have been controversial. The main focus, for these purposes, is on normal modal logics, though some attention is given to the non-normal side of the picture.