Introduction

I’m going to be upfront with you here: this book will lie to you. Again, and again, and again.

This is deliberate. If I told you the whole truth at every stage, you’d just quietly put the book down and back away slowly.

The lies in this book are not traps. They’re scaffolding – and like all scaffolding, they’re meant to be removed once they’ve done their job.

I’ll never punish you for not knowing something you haven’t been taught yet.

So, I’m going to tell you just enough truth at each stage so that you can understand what I’m telling you. Don’t worry if you’re confused. That’s expected, and it won’t last.

When something stops making sense, it’s because we’ve reached the edge of an explanation that was useful a moment ago. The next chapter will always be there to pick things up again.

If everything in this book feels immediately clear, you’re probably reading it too quickly. Give it chance to sink in.

This book is not a reference manual. It’s not a crash course, and it’s not a nostalgia tour.

You won’t learn how to write assembly language quickly. You also won’t find recipes, shortcuts, or “clever tricks” presented without explanation.

That’s because this book isn’t about accumulating techniques. It’s about learning how and when those techniques become necessary.

You don’t need to memorise every line. You need to learn to notice the moment when your explanation stops being good enough.

Almost everything in this book happens on one computer, the Sinclair ZX Spectrum. Now and then, though, another machine will wander in: a ZX81, a BBC Micro, a Commodore 64, a Nintendo Entertainment System, and once or twice an Amstrad CPC or an MSX.

They’re not here for a tour. Each one turns up at the moment it shows that the Spectrum’s way of doing something was a choice, not a law of nature. When you see three machines solve the same problem three different ways, you stop asking “is this how computers work?” and start asking “why did they build it like this?” That second question is the one this book is really about.

You won’t need any of these machines, or an emulator, to read it. Where there’s code, it’s there to be read, not typed, and you’ll see what it does on the page. Every listing has been run, and every picture of a screen was taken from a machine running it.