Each chapter is dedicated to a single topic: Nitrox, trimix, over-confidence, lack of experience, cave diving, wreck diving, decompression sickness, dry suits, lack of maintenance, navigation, rebreathers, following rules, and so on. Ange presents a scenario, describes what happenes, often to the bitter end, then analyzes the situation and closes the chapter with a set of rules on how the accident could have been avoided.
What makes the book extra valuable is the technical explanations inserted into each chapter. They explain, in plain English, the underlying concepts, physics, and technology. Likewise, the book's lenghty introduction serves as a Scuba 101 course (and is actually named "Scuba 101"). It is clear and concise and contains a lot of good information.
You will also quickly find that Ange heavily leans on some common sense guidelines: Follow the rules, always. Don't do anything you are not trained to do. Take diving and equipment maintenance very seriously.
Layout and graphics are basic. Do not look for colors and fancy graphics. And if you do not wish to know the outcome of each chapter right upfront, skip the intros that give them away. I have no idea why they are there.