Translated into English the title of the book means “the work of art in architecture”.
The contents of this book analyze the writer’s trip to Italy and their findings. Peyre doesn’t talk about the principles of architecture, but rather writes a token of respect for the ancient roman architects and shows her admiration of said buildings.
She was an architect herself and went to Rome for a higher education.
The book was written in the late 18th century. This context helps us understand Peyres admiration of those work of arts (as she would call them) because we’re amidst the enlightenment, were people started to rediscover past principles.
It isn’t particularly thick, there are 71 manageable pages. The book is illustrated and always shows a drawing to a little descriptive text (no more than one page). Those drawing are impressive in size and accuracy. The book itself is already roughly A3-sized and some pages fold out to reveal a drawing in the size A1. The drawings are usually floor plans, cuts or front views of anything ranging from a church to a palace to a fountain.
Peyre addressed her book to the current king Louis XV. Therefore, I assume that she wanted to influence the current architecture into a more ancient roman direction.
What’s interesting is that her writing proposed that building in this ancient roman style would almost magically make a city more desirable and all the beauty of the structures would solve every city’s problem.
Truth be told, although it wasn’t her work alone, the public taste seemed to shift in this direction with Neoclassicism right around the corner.