There are a few! Depending on what aspect / approach you prefer. These four are my favourites: "The Nature of Order" (four books!) is the most extensive - beau

There are a few! Depending on what aspect / approach you prefer. These four are my favourites: "The Nature of Order" (four books!) is the most extensive - beautiful, comprehensive, a little overwhelming, he lays out a broad philosophy of how built up spaces can foster life. Lots of visual examples, but gets pretty conceptual and abstract too. "The Timeless Way of Building" is a bit more focused, centers around the architectural concerns. More compact, more practical than the Nature of Order. "Pattern Language" -- you'll see that one suggested a lot. He lays out the concepts of interacting patterns ("best practices") that act on a variety of scales, some more generic, some more abstract. It's less of a read than a reference, but a few chapters lay out the motivations. "Notes on the Synthesis of Form" - the most far out one of the four suggestions, abstract, philosophical, a rarefied read. Dissects the essence of concepts, defines what "form" is -- fascinating read for sure, and not too long.