The Rustonomicon is your guidebook to the dark arts of unsafe Rust. It’s also sometimes called “the ’nomicon.”

The Rustonomicon digs into all the awful details that you need to understand when writing Unsafe Rust programs.

Should you wish a long and happy career of writing Rust programs, you should turn back now and forget you ever saw this book. It is not necessary. However if you intend to write unsafe code — or just want to dig into the guts of the language — this book contains lots of useful information.

Unlike The Rust Programming Language, we will be assuming considerable prior knowledge. In particular, you should be comfortable with basic systems programming and Rust. If you don’t feel comfortable with these topics, you should consider reading The Book first. That said, we won’t assume you have read it, and we will take care to occasionally give a refresher on the basics where appropriate. You can skip straight to this book if you want; just know that we won’t be explaining everything from the ground up.

This book exists primarily as a high-level companion to The Reference. Where The Reference exists to detail the syntax and semantics of every part of the language, The Rustonomicon exists to describe how to use those pieces together, and the issues that you will have in doing so.