This book has been developed by the Cambridge Open Learning Project in conjunction with the Cambridge University Press South African Branch. It offers a high quality learning resource to support the Cambridge Local Examinations Syndicate Syllabuses at HIGCSE level. The book is designed with distance learners in mind, but can also be used in the classroom. Each module is divided into neatly structured units, with learning objectives at the beginning and summaries at the end. The book encourages self-assessment by providing frequent activities and feedback, as well as a 'check your progress' exercise after selected units. It is written in a student-friendly style to encourage interactive learning, and the development of a range of skills needed for HIGCSE examinations.