Mathematical logic is a fundamental tool in computer science which has wide and significant applications. Recently, there has been a move towards using logic as a programming language and the considerable interest in Prolog can be seen as a step in this direction. Although formal logic is clearly a fundamental part of any degree programme, most of the current texts are designed for third year undergraduate or postgraduate mathematicians. This text is designed specifically for undergraduates and, together with A First Course in Formal Language Theory and A First Course in Computability, both by V. J. Rayward-Smith, it covers the important theory which should be in any computer science degree course.