The last chapter of this book is a short one, because the real story isn’t over. Toly, Tick, Vera, Pim and even Mr. Croak climbed a hill at dawn and found an enormous open book with nothing written in it.

“What goes here?” asked Pim, pen at the ready. Toly shrugged, happily. “Whatever people make next.” Tick ticked and Vera checked her watch. Mr. Croak tried to sell the blank pages, and for once nobody stopped him, because nobody was buying.

Networks keep changing. While this book was being made, Solana’s developers were getting ready to ship Alpenglow, a new consensus protocol designed to replace Tower BFT. Under its design, Proof of History would stop pacing block production. It was already switched on for devnet, the test network, but not yet on mainnet. So the clock in chapter three is already turning into history.

We won’t tell you how that turns out, what anything will be worth, or what happens next. Nobody knows. Anyone who says they do is probably a frog.

The ideas in this book will still matter whatever happens. How do you put events in order? How do you agree without a boss? When can work run side by side? Who holds the keys, and what do you do when everything stops?

This is the one page in the book that belongs entirely to you, reader. Write the first line of whatever comes next: something you’d like to learn, build or go and explore. It stays in this browser on this device, and nobody else will see it.

If you want to keep going for real, the official Solana documentation is a good place to start, and so are the sources tucked behind every chapter. Read them, poke at them, ask questions.

And if you ever meet a pocket clock that won’t stop ticking, listen to it. It might have an idea.