About This Book

I wrote The Product Flywheel because I was tired of watching talented PMs burn millions of dollars chasing vanity metrics while their products slowly died from the inside out.

Over fifteen years, I've built, scaled, and rescued products across four continents—from EdTech startups in London to FinTech platforms in Lagos, B2B SaaS tools in Berlin to AgriTech systems in Nairobi. I've watched companies celebrate hitting 500,000 users one quarter, only to see their retention collapse the next. I've seen brilliant engineers waste months building features nobody uses. And I've witnessed the heartbreak of founders realizing—too late—that their "growth" was just expensive user acquisition masking a fundamentally broken product.

This book is the playbook I wish I'd had when I started.

What This Book Is

The Product Flywheel is a practitioner's guide to designing products that grow themselves. It's about replacing the exhausting, expensive, linear funnel model with self-sustaining loops where each user makes the product better, faster, and more valuable for the next user. It's about building momentum that compounds, not campaigns that decay.

This isn't theory. Every framework, every metric, and every trade-off in this book comes from real products, real failures, and real breakthroughs. The $10 million burn story in Chapter 1? I lived it. The 5-second wait that killed conversions in Mumbai? I diagnosed it. The API that unlocked Africa? I helped build it.

Who This Book Is For

You should read this book if you are:

• A Product Manager who's tired of the feature factory treadmill and wants to build products that actually scale
• A Growth PM whose acquisition costs keep rising while retention stays flat
• A founder building in an emerging market where trust and infrastructure challenges make traditional playbooks useless
• An engineering leader frustrated by organizational misalignment between Product and Growth teams
• Anyone responsible for sustainable growth who suspects there's a better way than constantly pouring money into paid ads

You'll get the most value if you:

• Have shipped at least one product and understand the basics of user acquisition and retention
• Are comfortable with metrics (though I explain everything you need)
• Care more about long-term compounding than quarterly vanity spikes
• Are willing to challenge your organization's sacred cows

What Makes This Different

Most product books give you frameworks divorced from reality. This book gives you frameworks forged in reality—across wildly different contexts.

Regional Context Throughout: Unlike books written exclusively from Silicon Valley's perspective, I explicitly address how flywheel principles work in emerging markets (Lagos, Mumbai, Jakarta) versus mature markets (London, Boston, Berlin). Infrastructure matters. Trust matters. Culture matters. You'll see how the same core principles adapt.

Systems Thinking, Not Feature Lists: This isn't a collection of growth hacks. It's a comprehensive system for thinking about products as kinetic engines governed by physics—momentum, friction, inertia. You'll learn to diagnose your product the way a mechanical engineer diagnoses a machine.

The Hard Trade-offs: I don't pretend every decision is easy. Every chapter includes the real trade-offs PMs face: short-term revenue vs. long-term health, quality vs. speed, openness vs. control. I tell you what I chose and why, including when I got it wrong.

Executable Frameworks: Chapter 13 is a step-by-step playbook you can start using Monday morning. Worksheets. Runbooks. OKR templates. Everything you need to define, build, and measure your first flywheel.

How to Use This Book

The book is structured in four acts:

Part I (Chapters 1-3): Understanding the Flywheel — Why linear funnels fail, what flywheels are, and the physics governing product growth. Read this first. It rewires your brain.

Part II (Chapters 4-7): Building the Flywheel — How to identify your core loop, design feedback systems, activate network effects, and align your organization. This is where you get your hands dirty.

Part III (Chapters 8-10): Optimizing the Flywheel — How to diagnose friction, fuel the loop sustainably, and scale through ecosystems. This is where good PMs become great PMs.

Part IV (Chapters 11-13): Mastering Compound Growth — How to think in systems, leverage AI/automation, and execute your first flywheel using the complete playbook. This is where you become a Compounding PM.

You can read it linearly, or jump to the chapter addressing your biggest pain point right now. Stuck on retention? Start with Chapter 5. CAC spiraling? Chapter 9. Organizational chaos? Chapter 7.

What You'll Walk Away With

By the end of this book, you will be able to:

✓ Diagnose whether your product has a flywheel or just a leaking funnel

✓ Design self-reinforcing loops where user actions create compounding value

✓ Measure flywheel health using velocity, K-factor, and retention curves instead of vanity metrics

✓ Eliminate the friction points killing your momentum

✓ Align Product, Growth, and Engineering around a single compounding goal

✓ Scale through ecosystems, APIs, and network effects that multiply your reach

✓ Build products where your next user costs less than your last user

More importantly, you'll stop feeling like you're on a treadmill, endlessly running faster just to stay in place. You'll start building products that gain mass, speed, and momentum—products that grow themselves.

A Final Note

Building a flywheel is harder than running campaigns. It requires patience, discipline, and the courage to say "no" to short-term wins that undermine long-term health. But once it starts spinning—once you see newer cohorts retaining better than old ones, once your organic acquisition outpaces your paid channels, once your switching costs become unbreakable—you'll never go back.

You'll have built something rare: a product that compounds.

Let's begin.

Henry Williams