How to Use This Book

This book is meant to be worked through, not skimmed. Each chapter pairs a narrative page like this one with a companion notebook: run it top to bottom, don’t just read it. Along the way you’ll see four recurring markers.

Marker	Purpose
Key Concept	The core idea, precisely defined
Activity	Hands-on challenge: fill in the ... yourself before moving on
Common Mistake	A bug pattern worth recognising on sight
Pro Tip	A production-grade habit