Why this book
Enterprise architecture is the practice of shaping an organization’s structure so that business strategy and technology work together effectively. That much is not in dispute. What goes wrong is everything after it.
There is a pattern to how EA practices fail. The models get more detailed, the governance gets heavier, and the people who make the real decisions stop showing up. The architecture is correct, and nobody uses it.
Lean Enterprise Architecture treats EA as a leadership discipline that connects strategy with execution and business with technology. It applies one rule throughout: start small, deliver value early, and expand only where the organization genuinely benefits. “Lean” here means prioritizing practical relevance over theoretical completeness, not minimizing page count.
What you will learn
- Position EA as a steering instrument that translates strategy into roadmaps and traceable decisions.
- Design business architectures with capability maps and use them to plan your application landscape.
- Drive enterprise transformation and change management with proven frameworks and patterns.
- Set up governance that works: project portfolio management, IT controlling, and the Three Lines of Defense applied to architecture, without heavyweight bureaucracy.
- Model and communicate with TOGAF, Zachman, ArchiMate, BPMN, DMN, UML and C4.
- Navigate today’s technology landscape, from cloud-native platforms and API-first integration to FinOps, and treat digital sovereignty under DORA, NIS2, GDPR and the Swiss DSG as an architectural concern.
- Work with artificial intelligence as an enterprise architect, from how LLMs work to the four risk tiers of the EU AI Act and what they demand of AI governance.
Who it is for
For enterprise, business and solution architects, IT strategists, and the transformation leads who work with them. Whether you come from a technical background moving toward strategy, or from a business background trying to understand technology decisions, the book meets you where you are.
It is also the lecture companion for the CAS Enterprise Architecture program at the Lucerne University of Applied Sciences and Arts, and built to stay on your desk afterwards. Nearly every chapter opens with learning objectives and closes with key takeaways. Two chapters depart from that pattern because both are wrap-ups. 28 of the 32 chapters map to a CAS module, and the remaining four add material the program does not cover: application landscape planning, integration architecture, and the two wrap-up chapters.
How this book was made
The book is built the way we teach teams to build software. The manuscript lives in a Git repository as plain text. A push to the main branch triggers Leanpub through a webhook, which builds a new PDF, EPUB and web version. There is no separate publishing step: every commit that ships produces a new version of the book.
Behind it are more than 400 commits, roughly 138,000 words and 99 diagrams, each one generated as SVG from code rather than drawn by hand. AI helped shape structure, draft and clarify passages, generate diagrams, run review passes and move between languages. At every stage the two of us remained the deciding minds. AI proposed, we chose.
