Composition of the book in terms of typography and illustrations
The text is organised in paragraphs that range between a bit more than page-long and a quarter of a page long. Usually the first word is printed in capitals and starts with a decorated square-letter, which is five or four lines high and equally wide. Unless there are drawings on the same page, there is usually a margin to the inner side of the book, that spans for about half the width of the text. When there are drawings on the same page, the text is sometimes organised as on the other pages and sometimes right next to the drawing. The font size ranges between 10pt and 16pt.
The drawings that accompany the text vary a lot. Whilst there are a few rather eloquently drawn frontal views of whole gates, most of it are sections or frontal views of details, most of which again are drawn in a very simple, schematic way. There are also some plan views, and again rather a lot of geometric illustrations, which describe the ratios of different elements and details of the ionic orders. To sum it up: Most of the illustrations are kept very simple and seem very easy to be understood.
The illustrations and drawings are scattered throughout the book, always accompanying and stressing what is written in the paragraphs of the text itself. Some take in whole page-widths and have their own little texts, yet most fit in nicely between the paragraphs. Sometimes there are even two such drawings on the same page.
Whilst not all of these illustrations are numbered or referenced, there is a system of lettering, that goes throughout the book. The first few letters A, B, C… are only given to drawings, but then sometimes they also appear at the bottom of plain text pages, assumably linking illustrations that did not fit in to where they belong to.
Although there is probably more space given to text than to images, they play a very important role in this book. It must have been important to the author to explain his ideas and discoveries in a very visually attractive way. There are a lot of them all over the book and they are kept in a very explanatory style.
Taking all this into consideration, the book offers a very detailed analysis of the ionic order. Therefore, using all these easily and quickly understandable illustrations, might have been possibly been used as a handbook, but also as a reference to how you should understand and read Vitruvius’ views on this matter.