diff --git a/Cargo.lock b/Cargo.lock
index 9df375c..9bba48f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -234,6 +234,31 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "613f8cc01fe9cf1a3eb3d7f488fd2fa8388403e97039e2f73692932e291a770d"
+dependencies = [
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5b82ac4a3c2ca9c3460964f020e1402edd5753411d7737aa39c3714ad1b5420e"
+dependencies = [
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.8.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "22ec99545bb0ed0ea7bb9b8e1e9122ea386ff8a48c0922e43f36d45ab09e0e80"
+
 [[package]]
 name = "crypto-common"
 version = "0.1.6"
@@ -371,6 +396,19 @@ dependencies = [
  "wasi",
 ]
 
+[[package]]
+name = "globset"
+version = "0.4.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "57da3b9b5b85bd66f31093f8c408b90a74431672542466497dcbdfdc02034be1"
+dependencies = [
+ "aho-corasick",
+ "bstr",
+ "log",
+ "regex-automata",
+ "regex-syntax",
+]
+
 [[package]]
 name = "handlebars"
 version = "5.1.2"
@@ -439,6 +477,22 @@ dependencies = [
  "unicode-normalization",
 ]
 
+[[package]]
+name = "ignore"
+version = "0.4.22"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b46810df39e66e925525d6e38ce1e7f6e1d208f72dc39757880fcb66e2c58af1"
+dependencies = [
+ "crossbeam-deque",
+ "globset",
+ "log",
+ "memchr",
+ "regex-automata",
+ "same-file",
+ "walkdir",
+ "winapi-util",
+]
+
 [[package]]
 name = "indexmap"
 version = "2.2.6"
@@ -563,6 +617,7 @@ dependencies = [
  "env_logger",
  "genawaiter",
  "html5gum",
+ "ignore",
  "insta",
  "log",
  "mdbook",
@@ -584,7 +639,6 @@ dependencies = [
  "tracing-log",
  "tracing-subscriber",
  "ureq",
- "walkdir",
 ]
 
 [[package]]
diff --git a/Cargo.toml b/Cargo.toml
index 0373c31..7d19314 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,6 +19,7 @@ anyhow = "1.0.47"
 env_logger = "0.11.0"
 genawaiter = { version = "0.99.1", default-features = false }
 html5gum = "0.5.7"
+ignore = "0.4"
 log = "0.4.0"
 mdbook = { version = "0.4.35", default-features = false }
 normpath = "1.0.0"
@@ -33,7 +34,6 @@ serde_yaml = "0.9.0"
 tempfile = "3.0.0"
 toml = "0.8.0"
 ureq = "2.0.0"
-walkdir = "2.0.0"
 
 # Increase minimum version requirements of transitive dependencies
 thiserror = "1.0.2"
diff --git a/src/preprocess.rs b/src/preprocess.rs
index 569c0d1..dd55e70 100644
--- a/src/preprocess.rs
+++ b/src/preprocess.rs
@@ -14,6 +14,7 @@ use std::{
 
 use aho_corasick::AhoCorasick;
 use anyhow::{anyhow, Context as _};
+use ignore::gitignore::{Gitignore, GitignoreBuilder};
 use log::log;
 use mdbook::{
     book::{BookItems, Chapter},
@@ -23,9 +24,9 @@ use normpath::PathExt;
 use once_cell::sync::Lazy;
 use pulldown_cmark::{CodeBlockKind, CowStr, HeadingLevel, LinkType};
 use regex::Regex;
-use walkdir::WalkDir;
 
 use crate::{
+    book::Book,
     latex,
     pandoc::{self, OutputFormat, RenderContext},
 };
@@ -97,19 +98,8 @@ impl<'book> Preprocessor<'book> {
         }
         fs::create_dir_all(&preprocessed)?;
 
-        for entry in WalkDir::new(&ctx.book.source_dir).follow_links(true) {
-            let entry = entry?;
-            let src = entry.path();
-            let dest = preprocessed.join(src.strip_prefix(&ctx.book.source_dir).unwrap());
-            if entry.file_type().is_dir() {
-                fs::create_dir_all(&dest)
-                    .with_context(|| format!("Unable to create directory '{}'", dest.display()))?
-            } else {
-                fs::copy(src, &dest).with_context(|| {
-                    format!("Unable to copy '{}' -> '{}'", src.display(), dest.display())
-                })?;
-            }
-        }
+        let ignore = build_ignore(&ctx.book)?;
+        copy_recursive(&ctx.book.source_dir, &preprocessed, &ignore)?;
 
         let mut chapters = HashMap::new();
         for section in ctx.book.book.iter() {
@@ -1275,6 +1265,77 @@ impl fmt::Debug for IndexedChapter<'_> {
     }
 }
 
+fn copy_recursive(src: &Path, dst: &Path, ignore: &Gitignore) -> anyhow::Result<()> {
+    for e in src
+        .read_dir()
+        .with_context(|| format!("Unable to read directory {src:#?}"))?
+    {
+        let cur = e?.path();
+
+        log::info!("Walk: {cur:#?}");
+
+        if ignore.matched(&cur, cur.is_dir()).is_ignore() {
+            log::info!("  Ignore");
+
+            continue;
+        }
+
+        if cur.is_dir() {
+            let dir = dst.join(cur.strip_prefix(&src).unwrap());
+
+            fs::create_dir_all(&dir)
+                .with_context(|| format!("Unable to create directory {dir:#?}"))?;
+
+            copy_recursive(&cur, &dir, ignore)?;
+        } else {
+            let dst = dst.join(cur.strip_prefix(&src).unwrap());
+
+            log::info!("  Copy to: {dst:#?}");
+
+            fs::copy(cur, &dst).with_context(|| {
+                format!("Unable to copy '{}' -> '{}'", src.display(), dst.display())
+            })?;
+        }
+    }
+
+    Ok(())
+}
+
+fn build_ignore(book: &Book) -> anyhow::Result<Gitignore> {
+    let root = book.root.canonicalize()?;
+    let mut src = book.source_dir.canonicalize()?;
+
+    let mut builder = GitignoreBuilder::new(&src);
+
+    let mdbook_ignore = src.join(".mdbookignore");
+    if mdbook_ignore.exists() {
+        if let Some(err) = builder.add(mdbook_ignore) {
+            log::warn!("Unable to load '.mdbookignore' file: {}", err);
+        }
+    }
+
+    loop {
+        let git_ignore = src.join(".gitignore");
+        if git_ignore.exists() {
+            if let Some(err) = builder.add(git_ignore) {
+                log::warn!("Unable to load '.gitignore' file: {}", err);
+            }
+        }
+
+        if src == root {
+            break;
+        }
+
+        let Some(parent) = src.parent() else {
+            break;
+        };
+
+        src = parent.canonicalize()?;
+    }
+
+    Ok(builder.build()?)
+}
+
 #[cfg(test)]
 mod tests {
     use super::Preprocessor;