First of all, I think this book presents a good effort to demonstrate the often overlooked relation between art and science. The author jam packed lots of materials to tell the story from both perspectives. It is overall entertaining. I feel however the author laid out many ideas, being fact or speculations. It lacks of insight to answer a very simple question: Why can we expect mathematical or scientific explanation to intuitive subjects such as art.
Man did not create golden ratio. It is physics. In the physical world it represents steady structure; In natural world it is the most efficient configuration. Human simply observe. It is nature tells us what is steady, what is safe, what is efficient, and therefore give our perspective of beauty. So there's no wonder how Leonardo da Vinci who observes the nature to its finest details can present us art work with divine beauty.
I'd like to add though, the later part of the book is actually more interesting than the first part. Although the contents do not contribute to this particular title and can be found in many other science history books.