This is a textbook for a "logic literacy" course, suitable for beginning graduate or advanced undergraduate courses. The goal is to introduce students to the logic they need to know in order to understand contemporary philosophy. It emphasizes breadth rather than depth. For example, it discusses modal logic and counterfactuals, but does not prove the central metalogical results for predicate logic, such as completeness and undecidability. (It does, however, discuss enough metalogic for students to understand what metalogic is all about. For example, it goes through completeness proofs in nonmodal and modal propositional logic.) Published by Oxford University Press, 2010.