The Elements of User Experience: User-Centered Design for the Web and Beyond

Garrett's five-layer diagram — strategy, scope, structure, skeleton, surface — became the canonical way UX is taught and discussed, and it did so because it solved a real communication problem: designers, developers, and product managers were talking past each other by conflating decisions that belong at different levels of abstraction. The book gave the field a shared vocabulary for distinguishing business objectives from content requirements from information architecture from visual design. Its influence is so pervasive that many practitioners use the framework without knowing its origin. The limitations are real — the layers suggest a cleaner separation than practice allows, and the model is better at describing than prescribing — but as a mental map for organizing the chaos of product decisions, nothing simpler has replaced it. Read it to understand the scaffolding beneath every UX conversation you have ever had.