Preface

This book establishes a doctrine of Human-Centered Systems Engineering for the design, governance, and evolution of digital systems.

The purpose of the book is to codify enforceable standards that can be consistently applied, tested, and upheld across teams and systems—serving, for now, as a scaffold for best practices rather than a showcase of their practical application, which is reserved for future work.

This edition serves three functions:

Defines non-negotiable, human-centered principles that must guide digital system behavior.
Provides operational directives for translating those principles into product requirements and engineering decisions.
Creates a shared organizational framework for evaluating, auditing, and evolving UX and AI-mediated systems.

How to read this book.

This is written as a field manual, not an essay—terse, absolute, and command-form by design. The register is deliberate: it is the doctrine language of the U.S. Army, where I served, carried into the discipline of human-centered systems. Directives are written to be met, not debated; a standard you can defer is not a standard.

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“Those who are in love with practice without knowledge are like the sailor who gets into a ship without rudder or compass and who never can be certain whither he is going. Practice must always be founded on sound theory.”

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Leonardo da Vinci. From “The Notebooks of Leonardo Da Vinci”. I. Prolegomena and General Introduction to the Book on Painting (between 1480 and 1519).

1. Human Cognition & Behavior

▶ How humans perceive, think, remember, and decide during interaction with the system. ▶ These govern whether the interface can be understood at all.

Mission statement

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Ensure systems respect the limits and strengths of human perception, attention, memory, and decision-making so interfaces can be understood and used with confidence.

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