Guadet’s overarching philosophy is “truth in architecture”: the fit between what a building is for and what it looks like. This late-nineteenth-century idea is often treated as a precursor to modernism’s “form follows function,” but Guadet’s version is different. Guadet cares less about structural literalism (what the structure is really doing) than about intelligibility (that the structure appears logical). A building should read as plausible at a glance and convey that it is safe.

Throughout the book, you will find a recurring tension over what to do with new materials and building requirements. His theory was clearly made for traditional materials and yields archetypically traditional-looking buildings when applied under the constraints of simple technologies. However, when applied to modern materials, as was increasingly common at the time, the theory sometimes started to contradict itself. Guadet is nuanced about this, admitting that architects still needed to figure out how to use the new materials in beautiful ways. He provides much practical advice about this and often breaks with his own theories when new materials come up. He constantly warns against revolutionary innovation, and I believe he would not have liked modern architecture; at the same time, he is convinced that architects need to move forward and innovate while remaining rooted in the forms of the past.

The core of Guadet’s teaching centers on typologies. Guadet presents a catalogue of building elements (i.e., walls, doors, windows, ceilings, stairs, roofs, etc.), and for each element he teaches the classical form and the logic behind it. He goes on to explain why every little detail of a building element looks the way it does. He believes that forms originate from logic, and that what is logical is beautiful. His teaching is therefore constantly focused on why things look the way they do. This “why” also often shapes the character of the building, even if the reason no longer applies. Indirectly, this creates a sort of catalogue of styles for each architectural element. Whether this “why” is really as important as Guadet argues doesn’t matter, I think, for it is a very good way to learn and remember traditional forms. After reading this book, you will notice many more details in traditional buildings, and knowing the stories about their origins will help you remember them.

From Volume II onwards, he does the same with building functions. He starts with houses and explains why a house looks the way it does. From there, he addresses all the major and minor building functions, from schools to hospitals, from churches to prisons. The idea is that, for example, the archetypal look of a school or a door comes from its functional requirements. Understanding the functional logic of a building helps you understand why a building looks the way it does, and helps you design, for example, an archetypal-looking school—even if today the functional requirements of a school may be slightly different, or can be realized using a different look.

Most traditional architecture books were highly focused on the classical orders and their proportions. These are the standards for the decoration of classical columns and their entabletures. Traditional teaching of architecture tends to start with these orders as classicists traditionally see the orders and their fixed proportions come back in every element of the building (e.g. decoration of walls, windows and doors). This can be tedious and confusing to modern people as the old books tend to start by teaching the name of each part of the order, their proportions and sometimes even tricks on how to draw them without explaining the context of how to use them.

Guadets treatment of the orders on the other hand is unique. He only addresses the orders later in Volume I and rather than explaining what the orders are supposed to look like, he explains why they once structurally made sense as they originated from construction in wood. This is a key example of Guadet's theory of "truth in architecture", as he argues the orders are so beautiful because they make perfect sense in wood even though in stone many of the practical wooden features have turned to mere decoration. At the same time the orders are not central to all architecture for Guadet. So when one wants a Gothic, Art-Deco or innovative look this book is much more useful than a book that treats the orders as the foundation of all architecture. 

Guadet promises to teach the absolute beginner, but his nineteenth-century beginners obviously came with a different background than a modern-day beginner. To address that, this new edition has added 162 definitions throughout the text to define words contemporary beginners may not know, each about 2–3 sentences, placed in special definition boxes. In the back of the book, all these definitions are repeated in alphabetical order for reference. The edition also adds 18 context boxes. These boxes are, on average, about half a page each. Their content ranges from historical context to interpretation for contemporary architects who want to learn from Guadet. These context boxes can be more subjective and may sometimes stimulate thought about contemporary architecture and the feasibility of revival ideas. The book comes with a new preface. The preface is an essay on why Guadet matters to our modern world, setting the stage for the book and motivating you to start your journey. 

The book also comes with a thorough language update compared to earlier English translations. The language is modernized and sometimes adds extra sentences to make passages easier to understand. The overall result is that the book reads more like a modern book than the 125-year-old text it really is. Earlier English translations also came without figures and required the French version for the 500+ figures in Volume I. This new edition merges the two into a single book and translates the figure captions and other text within the figures.

Not necersarrily. This is a commonly held misconception about the École des Beaux-Arts, so even though the style is named after the school, the school didn't teach the style and didn't recognize that style at the time. Guadet was in fact strongly opposed to teaching style and was against the use of examples by architects still alive. Since most of the Beaux-Arts architects were still alive during the writing of the book you will barely be able to find a single Beaux-Arts styled building used as example in the books. That being said the pioneers of the Beaux-Arts style were mostly trained at École des Beaux-Arts at the time that Guadet was a teacher and student there, using the principles of this book. However, the contents of this book can also lead to different styles as many pioneers in the Art Deco and Art Nouveau movements were also trained at the École des Beaux-Arts using this same content. Furthermore, the teachings could even be applied to Gothic or Romanesque revival and there are many examples of Gothic and Romanesque architecture in the book.

Hopefully soon. This depends on demand and the time I have available to work on it. Please sign up to the mailing list to signal demand to me and be the first to be notified when the new volumes are ready. 

No. In general Guadet tries to stay away from style debates. Occasionally something slips out, showing  that Guadet was liberal for his time and that he was open-minded to different styles and innovation. Many architectural pioneers (particular in Art Nouveau and Art Deco) were trained at the École des Beaux-Arts or even personally mentored by Guadet. Especially in the older parts of the book he is actively promoting innovation whereas in the newer parts he occasionally complains that traditional architecture is out of fashion. That being said you must place Guadet into his historical context and when he thinks about innovation, he thinks about Art Nouveau and the Beaux-Arts style not what we call modern today.  Also many of his principles go directly against common practices in modern architecture today but at the same time do not exclude innovation or all modern architecture.  This can make the book useful to both modernist and revivalists. It could help modernists create new styles using traditional priniciples and for revivalists this could be a guide to authentically build in the old styles without excessive copying.

In general I expect both modernist and revivalists to strongly disagree with some things that Guadet has to say about architecture, as he didn't write for these contemporary groups. Furthermore, some of the context boxes do directly address some of the style debates that Guadet's text may raise to a modern audience. In them I tried to be interpreted Guadet objectively as far as possible, trying to not let my own views shine through too strongly. The context boxes particularly often address the obvious question that Guadet raises to a modern audience about whether revival is possible.  I try to point to numerous practical problems with revival ideas but at the same time I take these ideas seriously. I believe this objective stance can arm modernists with reasonable arguments against revivalism and it can point revivalist to the pitfalls in their plans so they can be avoided.  As such I hope to continue Guadet's neutral stance in style debates  and his pursuit of truth, even though I understand that the mere existance of this new edition is in itself not completely neutral.

Ornament  falls under Guadet's principle of moral truth. That means that the ornament must align with the statement one want to give with the building. This depends on the purpose of the building, the users and the culture of the society the building is placed in. However, Guadet is blunt about buildings without ornamentation. In Volume I, Book II, Chapter 3, he states: “A people who would see nothing in architecture but utility, and who, to that end, renounce beauty, would renounce civilization itself.” He also presents many types of decoration as a kind of catologue of styles to choose from, although this is at an abstract level. Unlike previous generation of architecture books (so called pattern books) he presents no decorations to be literally copied. 

Guadet wrote for the 19th century beginner. Through language updates, context and definition boxes this edition aims to make the book accessible to the contemporary beginner. Most of the book is therefore very accessible to a contemporary general audience. The only pre-requisite that is likely to be a problem for many readers is geometrical skills. These are today no longer taught at the same depth in schools as one hundred years ago. The main challenge in this new edition was to make those sections readable and this wasn't possible in all cases. However, the vast majority of the information in the book should be easy to process for contemporary beginners and in all other cases I aimed to ensure that the most important big picture points remained easy to grasp.

It's not abridged and for simplifications, generally the goal was not to remove any information. In a number of cases small clarifications are conservatively added to make the text more readable and in a few cases entire sentences were added for that reason. However, this was only done as minor language clarification, for larger clarifications context and definition boxes are used.

In a handful of rare cases (mostly in the chapter on vaults), I have omitted short passages to prevent confusion. They depend on advanced descriptive geometry (projection-based solid geometry) that is no longer widely taught to general readers. However, in most cases I decided to keep these complex geometrically descriptions in. My guiding principles here was the importance to the bigger picture and whether figures could help clarify them to a determined reader. 

No, but he is heavily biased towards French and Italian architecture. My rough estimate is that 50% of the examples are French, 40% Italian and about 10% are from other European countries and the Middle East. He does cover both medieval and ancient styles. These styles are somewhat similar throughout western countries.  So Guadet is a good source for traditional western architecture in general but he may not cover more localized styles beyond France. For traditional architecture from outside western countries he can only offer principles about looking to the past for architectural forms but no specifics.