The Design of Everyday Things

Don Norman's 1988 (revised 2013) argument that bad design is the designer's fault, not the user's — introducing affordances, signifiers, feedback, conceptual models, and the seven stages of action — the most widely assigned design book in the world.

Created the vocabulary of user-centered design — Norman's concepts (affordances, mental models, feedback loops, error design) gave designers a psychological framework for evaluating and improving usability; his central claim (if users struggle with a design, the design failed, not the user) was radical in 1988.