This textbook provides a first introduction to mathematical logic which is closely attuned to the applications of logic in computer science. In it the authors emphasize the notion that deduction is a form of computation. Whilst all the traditional subjects of logic are covered thoroughly: syntax, semantics, completeness, and compactness; much of the book deals with less traditional topics such as resolution theorem proving, logic programming and non-classical logics - modal and intuitionistic - which are becoming increasingly important in computer science. No previous exposure to logic is assumed and so this will be suitable for upper level undergraduates or beginning graduate students in computer science or mathematics. From reviews of the first edition: "...must surely rank as one of the most fruitful textbooks introduced into computer science ...We strongly suggest it as a textbook ..." SIGACT News