This new edition of the bestselling computing textbook, previously published by letts educational, has been revised and updated to meet the demands of the new modular computing specifications as offered by the various examining boards from September 2000. It is divided into units which correspond to the modules of the advanced subsidiary and Advanced level computing offered by the Ada examining Board and will be ideal for these courses. Centres using other 'a' Level computing specifications will find that this comprehensive text covers almost all of the required topics in an accessible and 'student-friendly' Way.