This book is a concise introduction to the key mathematical ideas that underpin computer science, continually stressing the application of discrete mathematics to computing. It is suitable for students with little or no knowledge of mathematics, and covers the key concepts in a simple and straightforward way. The theoretical ideas are constantly reinforced by worked examples and each chapter concludes with a mini case study showing a particular application. This provides further motivation to the reader to engage with the mathematical ideas involved, as well as demonstrating how the mathematics can be applied within a computing context. The book also contains carefully selected exercises for which full worked solutions are provided.