Unlike most modal logic textbooks, which are both forbidding mathematically and short on philosophical discussion, Modal Logics and Philosophy places its emphasis firmly on showing how useful modal logic can be as a tool for formal philosophical analysis. In Part 1 of the book, the reader is introduced to some standard systems of modal logic and encouraged through a series of exercises to become proficient in manipulating these logics. The emphasis is on possible world semantics for modal logics and the semantic emphasis is carried into the formal method, Jeffrey-style truth-trees. Standard truth-trees are extended in a simple and transparent way to take possible worlds into account. Part 2 systematically explores the applications of modal logic to philosophical issues such as truth, time, processes, knowledge and belief, obligation and permission. The second edition sees the addition of two new chapters on conditionals. The first, in Part 1, presents the formalities of a range of conditional logics, and the second, in Part 2, discusses some of the philosophical issues raised by them. Other chapters have been revised and updated, including some reordering of content in Part 1, to strengthen the book as a fully comprehensive introduction to modal logics and their application suitable for course use.