This is the fourth title in a new family of "informatics" textbooks covering the broad spectrum of IT topics for college-level students on BTEC, City and Guilds, or professional courses with IT components, or students of computer studies. The books are characterized by active learning strategies, and each chapter is prefaced with a list of achievement goals, includes examples, case studies, exercises and possible model answers. The exercises are applicable to a range of equipment. The series is produced in association with the Information Technology Unit of Buckinghamshire College of Higher Education and edited by Roger Carter, Reader in Information Technology in the ITU.