# Advanced Features

We've come a long way! By now, we've learned 99% of the things you'll need to know when writing Rust. We'll wrap the book up by doing one more project, but before we get to that, let's talk about a few things that you may run into that last 1% of the time. Feel free to skip this chapter and come back to it once you run into these things in the wild; the tools we'll learn to use here are useful in very specific situations. We don't want to leave them out, but you won't find yourself reaching for them often.

Here's a quick summary:

- Unsafe Rust: for when you need to tell Rust "just trust me, promise!"
- Advanced Lifetimes: Additional lifetime syntax for complex situations.
- Advanced Traits: Associated Types, coherence, and disambiguation.