Without knowing any better, the title of the book “the theory of perspective demonstrated” makes me think it will talk about the importance of perspective and how it can largely impact our perception of things, such as for example a builing. The book doesn’t have a list of content but there is a short preface in which John Cowley describes his intent with this book. He says that he is devoted to conveying his mathematical knowledge to his students in the easiest way possible. John Cowley was a professor of mathematics at the royal military academy in London. Math wasn’t the only thing he excelled at though. He was also a cartographer and geologist to King George II. Even before that preface, there is a sort of dedication to John Manners, a local Lord. The rest of the book is organized into different chapters such as “a succinct history of perspective”. At the end of the book there are many pages filled with simple illustrations. They are all very simple straight-line drawings with minimal shading. In my opinion having illustrations in a book like this makes a lot of sense, since demonstrating perspective is a lot easier to do with drawings instead of words. The illustrations help better demonstrate what John Cowley is talking about in the written part of the book. “The theory of perspective demonstrated” is not a very large book in format but it is quite thick, having over 270 pages.