This course is an introduction to formal logic. We’ll study techniques for translating natural language sentences into the more precise language of first-order logic. The sentences of this formal language lack the ambiguity that is common to natural language expressions, and so allow for a rigorous study of the logical relations that exist between them. That account takes the form of a system of proof: a set of inference rules which allows us to determine precisely when one sentence follows logically from another set of sentences. Hence by learning a system of proof we learn a method for determining the validity of arguments.