diff --git a/app/src/main/java/one/nem/lacerta/MainActivity.java b/app/src/main/java/one/nem/lacerta/MainActivity.java
index e97093e1..725c1063 100644
--- a/app/src/main/java/one/nem/lacerta/MainActivity.java
+++ b/app/src/main/java/one/nem/lacerta/MainActivity.java
@@ -5,6 +5,7 @@ import androidx.appcompat.widget.Toolbar;
 import androidx.core.content.ContextCompat;
 import androidx.fragment.app.Fragment;
 import androidx.fragment.app.FragmentManager;
+import androidx.fragment.app.FragmentTransaction;
 import androidx.navigation.NavController;
 import androidx.navigation.fragment.NavHostFragment;
 import androidx.navigation.ui.NavigationUI;
@@ -110,4 +111,47 @@ public class MainActivity extends AppCompatActivity implements FragmentNavigatio
                     .commit();
         }
     }
+
+    @Override
+    public void navigateToFragment(Fragment fragment, boolean addToBackStack, boolean clearBackStack) {
+        if (clearBackStack) {
+            getSupportFragmentManager().popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
+        }
+        if (addToBackStack) {
+            getSupportFragmentManager().beginTransaction()
+                    .replace(R.id.nav_host_fragment, fragment)
+                    .addToBackStack(null)
+                    .commit();
+        } else {
+            getSupportFragmentManager().beginTransaction()
+                    .replace(R.id.nav_host_fragment, fragment)
+                    .commit();
+        }
+    }
+
+    public void navigateToFragmentAlternate(Fragment fragment, boolean addToBackStack) {
+        FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
+
+        // get the current fragment
+        Fragment currentFragment = getSupportFragmentManager().getPrimaryNavigationFragment();
+
+        // hide the current fragment
+        if (currentFragment != null) {
+            transaction.hide(currentFragment);
+        }
+
+        // Add the new fragment
+        transaction.add(R.id.nav_host_fragment, fragment);
+
+        // Add the transaction to the back stack if needed
+        if (addToBackStack) {
+            transaction.addToBackStack(null);
+        }
+
+        // Commit the transaction
+        transaction.commit();
+
+        // Update the primary navigation fragment
+        getSupportFragmentManager().beginTransaction().setPrimaryNavigationFragment(fragment).commit();
+    }
 }
diff --git a/feature/library/src/main/java/one/nem/lacerta/feature/library/LibraryPageFragment.java b/feature/library/src/main/java/one/nem/lacerta/feature/library/LibraryPageFragment.java
index b968693d..905fafa8 100644
--- a/feature/library/src/main/java/one/nem/lacerta/feature/library/LibraryPageFragment.java
+++ b/feature/library/src/main/java/one/nem/lacerta/feature/library/LibraryPageFragment.java
@@ -81,6 +81,16 @@ public class LibraryPageFragment extends Fragment {
         return fragment;
     }
 
+    public static LibraryPageFragment newInstance(String folderId) { // Back action
+        LibraryPageFragment fragment = new LibraryPageFragment();
+        Bundle args = new Bundle();
+        args.putString("folderId", folderId);
+        args.putString("title", null);
+        args.putString("publicPath", null);
+        fragment.setArguments(args);
+        return fragment;
+    }
+
     public static LibraryPageFragment newInstance() {
         LibraryPageFragment fragment = new LibraryPageFragment();
         Bundle args = new Bundle();
@@ -127,11 +137,13 @@ public class LibraryPageFragment extends Fragment {
         super.onViewCreated(view, savedInstanceState);
 
         if (getArguments() != null) {
-            this.folderId = getArguments().getString("folderId");
-            this.title = getArguments().getString("title");
-            this.parentId = getArguments().getString("parentId");
-            // Log
-            logger.debug("LibraryTopFragment", "Args: folderId: " + folderId + ", title: " + title + ", parentId: " + parentId);
+            this.folderId = getArguments().getString("folderId"); // Required
+            if (getArguments().getString("title") == null && getArguments().getString("publicPath") == null) {
+                this.libraryItemPage = new LibraryItemPage();
+            } else {
+                this.title = getArguments().getString("title");
+                this.parentId = getArguments().getString("publicPath");
+            }
         } else {
             logger.debug("LibraryTopFragment", "getArguments() is null(maybe root)");
             this.libraryItemPage = new LibraryItemPage();
@@ -150,7 +162,7 @@ public class LibraryPageFragment extends Fragment {
                 // 画面遷移
                 FragmentNavigation fragmentNavigation = (FragmentNavigation) getActivity();
                 // folderId: 推移先で表示するフォルダのID, folderName: 推移先で表示するフォルダの名前, parentId: このフラグメントで表示しているフォルダのID(推移先の親)
-                fragmentNavigation.navigateToFragment(LibraryPageFragment.newInstance(folderId, folderName, libraryItemPage != null ? libraryItemPage.getParentId() : null));
+                fragmentNavigation.navigateToFragment(LibraryPageFragment.newInstance(folderId, folderName, libraryItemPage != null ? libraryItemPage.getParentId() : null), false);
             }
 
             @Override
@@ -165,6 +177,16 @@ public class LibraryPageFragment extends Fragment {
         // Get library page and update RecyclerView items
         lacertaLibrary.getLibraryPage(this.folderId, 10).thenAccept(libraryItemPage -> {
             this.libraryItemPage = libraryItemPage;
+
+            if (this.parentId == null) {
+                this.parentId = libraryItemPage.getParentId();
+            }
+            if (this.title == null) {
+                this.title = libraryItemPage.getPageTitle();
+                // Toolbar init again
+                toolbarSetup(view.findViewById(R.id.library_toolbar), this.folderId != null, this.title != null ? this.title : "ライブラリ");
+            }
+
             logger.debug("LibraryTopFragment", "Item selected! Total item page: " + this.libraryItemPage.getListItems().size());
             getActivity().runOnUiThread(() -> { // TODO-rca: 実行条件を考える？
                 listItemAdapter.notifyItemRangeRemoved(0, this.libraryItemPage.getListItems().size() - 1);
@@ -228,8 +250,8 @@ public class LibraryPageFragment extends Fragment {
             if (showBackButton) {
                 toolbar.setNavigationIcon(one.nem.lacerta.shared.ui.R.drawable.arrow_back_24px);
                 toolbar.setNavigationOnClickListener(v -> {
-                    this.libraryItemPage = lacertaLibrary.getLibraryPage(this.libraryItemPage.getParentId(), 10).join();
-                    getParentFragmentManager().popBackStack();
+                    //this.libraryItemPage = lacertaLibrary.getLibraryPage(this.libraryItemPage.getParentId(), 10).join();
+                    processBack();
                 });
             } else {
                 toolbar.setNavigationIcon(null);
@@ -247,4 +269,17 @@ public class LibraryPageFragment extends Fragment {
         });
     }
 
+    /**
+     * Backボタンが押された時の処理
+     */
+    private void processBack() {
+        if (this.parentId != null) {
+            FragmentNavigation fragmentNavigation = (FragmentNavigation) getActivity();
+            fragmentNavigation.navigateToFragment(LibraryPageFragment.newInstance(this.parentId));
+        } else { // Root
+            FragmentNavigation fragmentNavigation = (FragmentNavigation) getActivity();
+            fragmentNavigation.navigateToFragment(LibraryPageFragment.newInstance());
+        }
+    }
+
 }
diff --git a/model/src/main/java/one/nem/lacerta/model/FragmentNavigation.java b/model/src/main/java/one/nem/lacerta/model/FragmentNavigation.java
index 0eb3487d..d9e4326c 100644
--- a/model/src/main/java/one/nem/lacerta/model/FragmentNavigation.java
+++ b/model/src/main/java/one/nem/lacerta/model/FragmentNavigation.java
@@ -6,4 +6,8 @@ public interface FragmentNavigation {
     void navigateToFragment(Fragment fragment);
 
     void navigateToFragment(Fragment fragment, boolean addToBackStack);
+
+    void navigateToFragment(Fragment fragment, boolean addToBackStack, boolean clearBackStack);
+
+    void navigateToFragmentAlternate(Fragment fragment, boolean addToBackStack);
 }