This is a book about A-Level Computer Science. It aims to fit in with the AQA and OCR GCE A-Level Computer Science syllabus but is not endorsed by either. It should be useful as a revision guide or to find alternative explanations to the ones in your textbook. If you haven't heard of an A-Level then this book probably won't be of much interest to you but you can find out about them at Wikipedia.
If any part of this book is unclear or even wrong then please post a comment on the discussion page or simply fix it yourself! In particular, please say if the book assumes any knowledge or skills which not all A-Level Computing students have.