Every organisation believes it has an architecture. Few can say what it actually is, or what it is quietly costing them to keep. Enterprise Architecture Debt argues that well-funded, well-governed transformations fail to deliver not from poor execution, but from the accumulated weight of ordinary, individually defensible decisions that were never reconciled against each other, and harden into constraints no one owns. Drawing on real transformation case studies across industries and company sizes, the book introduces Enterprise Architecture Debt as a distinct, measurable condition: not a rebrand of technical debt, but a structural pattern that grows between systems rather than inside them, and stays invisible because nothing breaks outright. Across eighteen chapters, the book shows readers how to name this debt, measure it using the Five Structural Indicators and the Architecture Debt Observatory, connect it to the business KPIs it undermines, and govern it through practical decision frameworks. It closes by reframing enterprise architecture as enterprise design: the discipline of intentionally shaping how an organisation operates, evolves, and decides. Three appendices turn the book's frameworks into artifacts a team can use immediately: a scored, tooling-free assessment, a metrics catalogue, and nine ready-to-use templates, including an Architecture Decision Record and an Enterprise Architecture Debt Register. Written for CIOs, CTOs, chief architects, enterprise and solution architects, and transformation leaders, this book gives practitioners language to name what they were already sensing, and gives leadership a way to see architecture debt before it becomes the reason a transformation fails to deliver what was promised.
