Deduction is an efficient and elegant presentation of classical first-order logic. It presents a truth tree system based on the work of Jeffrey, as well as a natural deduction system inspired by that of Kalish and Montague.Efficient and elegant presentation of classical first-order logic. Presents a truth tree system based on the work of Jeffrey, as well as a natural deduction system inspired by that of Kalish and Montague. Contains detailed, yet accessible chapters on extensions and revisions of classical logic: modal logic, many-valued logic, fuzzy logic, intuitionistic logic, counterfactuals, deontic logic, common sense reasoning, and quantified modal logic. Includes problem sets, designed to lead students gradually from easier to more difficult problems. Further information and select answers to problems available here: http://bonevac.info/deduction/About_the_Book.html