Absolutely frustrating book to read. WAY TOO MUCH FILLER. Honestly I don't know how you can lengthen such simple concepts to such a large degree. When reading this book you're not just learning computer science, oh no this book will teach you all the history in the world and in the end start with a "Nowadays" and give you the few points which are actually in the syllabus. All this does is deter people from picking up computer science or they actually drop it when they look at this needlessly giant book which is more like a paperweight. Also when you have to revise for the exam all that's going through you're mind is how will you finish the book before your exam thanks to it's pointless summary boxes which are only naming things from the chapter summarizing absolutely nothing only wasting your time. Computer Science is not as hard as it is being made to be in this book.
This is possibly the worst endorsed book to have ever existed, I'm serious, you are very much better off using free online resources, this book won't be of much use to you.
I really really hope for the next edition they work on it and strictly ONLY cover the syllabus itself, because you're really not helping anyone with this time waster.