# Associated Types

The first edition of the book is no longer distributed with Rust's documentation.

If you came here via a link or web search, you may want to check out [the current
version of the book](../ch20-03-advanced-traits.html#specifying-placeholder-types-in-trait-definitions-with-associated-types) instead.

If you have an internet connection, you can [find a copy distributed with
Rust
1.30](https://doc.rust-lang.org/1.30.0/book/first-edition/associated-types.html).
