#A note from the author

I always wanted to know, properly know, what a computer does. Not in the hand-waving sense where someone says “and then the operating system handles it” and you nod along. I mean from the bottom: from sand and electricity up through the gates and the clock and the instructions, all the way to a program doing something in the world. I wanted there to be no point at which I had to take a step on faith.

I tried, over the years, to find a single book that would take me there. There are great books about parts of the journey. There are textbooks that cover the whole thing but at a level that assumes you already understand most of what you are trying to learn. There are popular accounts that are warm and funny but step over the actual mechanism. None of them was the book I wanted.

Then I read Carson Gross’s The Grug Brained Developer. It is a short essay, written in the voice of a caveman, about the reality of being a software engineer. It is also one of the most honest pieces of writing about software I have ever read. The voice is plain and the ideas are deep, and the gap between those two things is what makes it work. By the end I trusted grug more than I trusted most authors who sound clever.

That is the book I wanted to read about computers. So I decided to write it.

There is one more reason for the voice, and it is more practical. English is not my first language. Writing flowing, polished English prose is hard for me, and trying to do it across hundreds of pages would have either produced something stilted or stopped me writing the book at all. Grug’s voice gives me a way out. Short sentences. Small words. Plain speech. It suits the ideas, and it suits me.

The promise of this book is the same one grug makes: nothing left as magic. Every piece of the machine gets earned before it is used. Every chapter starts with a problem somebody actually faced, and ends with that problem solved, with a new problem waiting. By the last page, the computer in your hand should feel less like a sealed box and more like something you could, in principle, rebuild from the ground up.

I am not pretending this is the only way to learn this material. It is the way I needed to learn it. If it works for you too, even better.