Book excerpt: "The rules of architecture have been discussed since the Roman architect and engineer Vitruvius coined the trilogy firmitas, utilitas and venustas, most commonly translated as firmness, commodity and delight. Put simply, this means that a building should stand up and endure, that it should serve its function, and that it should give pleasure to its users and the wider community. Great buildings, like great art, contain something that is impossible to define or pin down. But that greatness, in almost all cases, overlays the principles set out in this book. While one cannot guarantee that a building will be great, if all the principles are followed, you will avoid the pitfalls to which too many are subject. This new title in our 10 Principles series provides clear explanations of each tenet along with useful illustrations to help the reader visualize what is being discussed. The author assumes no background on the subject, but an interest in learning more about what goes into making a building work. An experienced writer on this subject, Ruth Slavid provides a useful and illuminating primer to the field that is accessible to students of architecture, architects or architectural historians or anyone interested in the principles behind the buildings that surround them."