Configure mdbook to use external dependencies via Cargo.toml, library paths, and book.toml preprocessors.
Use --library-path to point to compiled dependencies, add external crates to Cargo.toml, and configure preprocessors in book.toml.
cd packages/trpl
cargo build
mdbook test --library-path packages/trpl/target/debug/deps
Add external dependencies like rand to Cargo.toml under [dependencies]. Configure custom preprocessors in book.toml under [preprocessor.trpl-note] or [preprocessor.trpl-listing] using cargo run commands.
Path, Git, and Registry Dependencies explain how to connect your book project to external code libraries and custom tools. You tell the build system where to find compiled code files, list needed packages in a configuration file, and define special scripts to run during the build process. Think of it as giving your project a map to find its tools and ingredients.