The book is as simple as possible and aimed at a non-technical audience with absolutely no knowledge of computers or electronics, but it is an electrical engineering text.
A typical page consists of a circuit diagram (or program) and a paragraph or two of explanation. The book begins with a VERY simple circuit and continues to a very complex circuit (a computer) while explaining everything. Everything has been made as simple as possible while leaving nothing out. Eighty-four circuit diagrams and some timing diagrams and short programs make every point clear.