For such a small book with such detailed drawings, the clarity is remarkable. Building in a pre-electrical age, with hand-wielded tools, one can only marvel at what these Middle Ages people managed to conceive, and what many more put together.
This book is technical. Architects, engineers and construction people of all kinds would get a lot out it because they would understand the full implications of what was achieved. Anyone else has to work a bit harder, but even this non-specialist found a lot to enjoy. It was clearly and simply written by someone who obviously loved what he was researching.