The detailed urban structure helps us to enjoy healthier lives, and to live them more fully. A new toolkit for adaptive design combines the design patterns of Christopher Alexander with recent results from perception science. Understanding the way people experience and interact with urban space selects from among a variety of design options. Our priority is human health and well-being, not subservience to design ideology. Standard industrial-modernist typologies turn out to degrade the urban experience, and should henceforth be abandoned. Older techniques that have long been suppressed for stylistic reasons proved to be far superior for human use and long-term health. Those updated traditional design tools need to be re-instated and applied. By adopting a science-based approach, our society can shape the built environment intelligently from today on.