Book: The Design of Everyday Things

Overview
Donald Norman offers a compelling, readable argument for designing products and systems around human needs, abilities, and limitations. He shows how everyday objects, from doors and stoves to telephones and software, can frustrate or delight depending on whether their design communicates clearly what actions are possible and how those actions will work. The central claim is simple and provocative: when people make errors or struggle, the fault usually lies with poor design rather than with the user.

Core Concepts
A handful of interrelated concepts form the backbone of Norman's explanation. Affordances describe the possible actions an object makes available, while signifiers are the cues that reveal those possibilities. Mappings cover the relationship between controls and their effects, and feedback provides immediate information about the outcome of actions. Constraints narrow the range of possible actions to help prevent mistakes, and a good conceptual model lets users form an accurate internal picture of how a system behaves.

Discoverability and Visibility
Norman emphasizes that users must be able to discover what actions are possible and perceive the results of their actions. Visibility of controls and the effects they produce reduces guessing and trial-and-error, enabling people to form reliable mental models. When affordances are hidden or signifiers are absent, even simple tasks become confusing; making functionality visible and understandable is central to usability.

Human Error and Design Responsibility
Rather than blaming users for mistakes, Norman reframes errors as opportunities to improve design. He distinguishes between slips, where the intended action is correct but the execution fails, and mistakes, where actions are guided by an incorrect goal or plan. Well-designed systems anticipate both types, reducing the chance of slips through clearer mappings and feedback, and reducing mistakes by simplifying choices and clarifying consequences.

Practical Examples and Everyday Cases
Norman peppers the narrative with vivid everyday examples that make abstract ideas tangible. He recounts frustrations with doors that require pushing when labeled "pull," stoves with ambiguous controls, and devices that lack clear feedback. These cases illustrate how small design changes, repositioning a handle, adding a clear indicator, or arranging controls to match natural mappings, can dramatically improve usability.

Design Process and Human-Centered Approach
Norman advocates an iterative, user-centered design process that incorporates observation, prototyping, and testing with real users. He stresses empathy for users and the need to understand their goals, tasks, and environment. Design should accommodate variability in user knowledge, skill, and context, and should support learning and recovery when errors occur.

Consequences for Technology and Policy
The principles outlined extend beyond physical objects to software, services, and systems. Norman warns that complexity and poor design in technological systems can lead to inefficiency, frustration, and even danger. He calls for designers, managers, and policymakers to prioritize usability as a fundamental aspect of product and system quality.

Legacy and Influence
Norman's accessible synthesis of psychology, engineering, and design helped crystallize the field of user-centered design and influenced generations of designers, engineers, and product managers. The ideas of affordances, signifiers, mappings, and feedback have become standard vocabulary in design discourse. The book's enduring appeal lies in its combination of practical guidance, memorable examples, and a clear ethical stance: good design respects and empowers people.