This book consolidates and extends three editorial pieces published on businessengineer.ai in early 2026 — the Anthropic Labs founder-cell analysis, The Product Overhang Doctrine, and The Anatomy of a Founder Cell. The trilogy is reframed here around the role at the center of the AI-era product organization: the Builder-PM.
Two new chapters anchor the structure. Part IV anatomizes the role in operating detail. Part V is the transition — written for individual PMs, PM leaders at incumbents, and founders hiring into AI-native cells. An appendix compiles the named mental models from the full work into a single field guide.
The book is built to be read straight through, but each part stands alone.
Individual PMs may want to start with Part IV (the role) and Part V (what to do Monday).
