The aim of this book is to provide an accessible text for students, covering each of the elements in the OCR GCSE (9-1) Computer Science specification J276. It will be invaluable both as a course text and in revision for students nearing the end of the course. It is divided into eight sections, each broken down into manageable chapters of roughly one lesson. Sections 5 and 6 of the textbook cover algorithms and programming concepts with a theoretical aroach to provide students with experience of writing, tracing and debugging pseudocode solutions without the aid of a computer. These sections would complement practical programming experience.