This book covers the area of digital logic, sitting above the level of physics and electronics. If you want to know how the elements of a computer work together logically, this is the book to read.
This book predates the trend towards maximising the number of pages in textbooks and as such, it is a relief to read with its clear and concise style. I started reading this book prior to commencing university study of computer science and was hooked by the authors' style of writing. It's nothing flashy or ground breaking, just a very diligent presentation of material in a logical sequence so that you almost effortlessly advance your knowledge. In summary, this book was both accessible to me as an enthusiastic amateur and later, useful right up to my fourth year in a bachelors degree.