* Intended for a course for students in philosophy, mathematics, linguistics, or computer science, and excellent for self-study. Motivation is given for each formal concept and each step in building a formal logic in terms of formalizing reasoning. Summaries are given at important junctures in the bookto keep students aware of what they are doing and where they are going. Criteria of formalization are developed and applied to formalizing ordinary language reasoning in an example-analysis format. More than 300 worked examples. More than 500 exercises with answers available on the web.