diff --git a/.travis.yml b/.travis.yml
index 4c01b9546..192557ec1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -53,13 +53,12 @@ before_script:
   - "if [ \"$BEHAT_TEST\" = \"1\" ] && [ \"$CMS_TEST\" = \"1\" ]; then (vendor/bin/serve --bootstrap-file cms/tests/behat/serve-bootstrap.php &> serve.log &); fi"
 
 script:
-  - "if [ \"$PHPUNIT_TEST\" = \"1\" ] && [ \"$CMS_TEST\" = \"\" ]; then vendor/bin/phpunit; fi"
+  - "if [ \"$PHPUNIT_TEST\" = \"1\" ] && [ \"$CMS_TEST\" = \"\" ]; then vendor/bin/phpunit tests/php; fi"
   - "if [ \"$PHPUNIT_TEST\" = \"1\" ] && [ \"$CMS_TEST\" = \"1\" ]; then vendor/bin/phpunit cms/tests; fi"
   - "if [ \"$BEHAT_TEST\" = \"1\" ] && [ \"$CMS_TEST\" = \"\" ]; then vendor/bin/behat --config tests/behat/config.yml .; fi"
   - "if [ \"$BEHAT_TEST\" = \"1\" ] && [ \"$CMS_TEST\" = \"1\" ]; then vendor/bin/behat @cms --config tests/behat/cms-config.yml; fi"
   - "if [ \"$NPM_TEST\" = \"1\" ]; then git diff-files --quiet -w; fi"
   - "if [ \"$NPM_TEST\" = \"1\" ]; then git diff -w --no-color; fi"
-  - "if [ \"$NPM_TEST\" = \"1\" ]; then yarn run test; fi"
   - "if [ \"$NPM_TEST\" = \"1\" ]; then yarn run lint; fi"
   - "if [ \"$PHPCS_TEST\" = \"1\" ]; then composer run-script lint; fi"
 
diff --git a/.upgrade.yml b/.upgrade.yml
index 11da32579..6d1db7c39 100644
--- a/.upgrade.yml
+++ b/.upgrade.yml
@@ -171,7 +171,7 @@ mappings:
   CMSBatchActionHandler: SilverStripe\Admin\CMSBatchActionHandler
   CMSMenu: SilverStripe\Admin\CMSMenu
   CMSMenuItem: SilverStripe\Admin\CMSMenuItem
-  CMSPreviewable: SilverStripe\Admin\CMSPreviewable
+  CMSPreviewable: SilverStripe\ORM\CMSPreviewable
   CMSProfileController: SilverStripe\Admin\CMSProfileController
   GroupImportForm: SilverStripe\Admin\GroupImportForm
   LeftAndMain: SilverStripe\Admin\LeftAndMain
diff --git a/composer.json b/composer.json
index 7319fe5cd..5d6f027aa 100644
--- a/composer.json
+++ b/composer.json
@@ -23,7 +23,6 @@
     "monolog/monolog": "~1.11",
     "nikic/php-parser": "^2 || ^3",
     "silverstripe/config": "^1@dev",
-    "silverstripe/admin": "^1@dev",
     "swiftmailer/swiftmailer": "~5.4",
     "symfony/cache": "^3.3@dev",
     "symfony/config": "^2.8",
@@ -32,6 +31,7 @@
     "vlucas/phpdotenv": "^2.4"
   },
   "require-dev": {
+    "silverstripe/admin": "^1@dev",
     "phpunit/PHPUnit": "~4.8",
     "silverstripe/behat-extension": "^2.1.0",
     "silverstripe/serve": "dev-master",
diff --git a/docs/en/04_Changelogs/4.0.0.md b/docs/en/04_Changelogs/4.0.0.md
index 313e4e91a..27eacda2e 100644
--- a/docs/en/04_Changelogs/4.0.0.md
+++ b/docs/en/04_Changelogs/4.0.0.md
@@ -52,6 +52,7 @@ guide developers in preparing existing 3.x code for compatibility with 4.0
 * i18n Updated to use symfony/translation over zend Framework 1. Zend_Translate has been removed.
 * Replaced `Zend_Cache` and the `Cache` API with a PSR-16 implementation (symfony/cache)
 * _ss_environment.php files have been removed in favour of `.env` and "real" environment variables.
+* admin has been moved to a new module [silverstripe/admin](https://github.com/silverstripe/silverstripe-admin).
 
 ## <a name="upgrading"></a>Upgrading
 
@@ -1141,6 +1142,7 @@ A very small number of methods were chosen for deprecation, and will be removed
   class which can be used to select the correct behaviour:
   * `HTMLText`: `DBHTMLText` with shortcodes enabled
   * `HTMLFragment`: `DBHTMLText` without shortcodes enabled (as default)
+* `CMSPreviewable` has been moved from the `SilverStripe\Admin` namespace to `SilverStripe\ORM`
 * Changes to `DBString` formatting:
   * `NoHTML` is renamed to `Plain`
   * `LimitWordCountXML` is removed. Use `LimitWordCount` instead.
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index cc1d4b96e..bbff0c2ec 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -20,7 +20,6 @@
 
 	<testsuite name="Default">
 		<directory>tests/php</directory>
-		<directory>admin/tests/php</directory>
 	</testsuite>
 
 	<listeners>
diff --git a/src/Assets/File.php b/src/Assets/File.php
index a115646e5..1482b6992 100644
--- a/src/Assets/File.php
+++ b/src/Assets/File.php
@@ -2,15 +2,13 @@
 
 namespace SilverStripe\Assets;
 
-use SilverStripe\Admin\AdminRootController;
-use SilverStripe\Admin\CMSPreviewable;
+use SilverStripe\ORM\CMSPreviewable;
 use SilverStripe\Assets\Storage\AssetNameGenerator;
 use SilverStripe\Assets\Storage\DBFile;
 use SilverStripe\Assets\Storage\AssetContainer;
 use SilverStripe\CMS\Model\SiteTree;
 use SilverStripe\Core\Convert;
 use SilverStripe\Control\Director;
-use SilverStripe\Control\Controller;
 use SilverStripe\Core\Injector\Injector;
 use SilverStripe\Dev\Deprecation;
 use SilverStripe\Forms\DatetimeField;
@@ -823,21 +821,6 @@ class File extends DataObject implements ShortcodeHandler, AssetContainer, Thumb
         return null;
     }
 
-    /**
-     * @todo Coupling with cms module, remove this method.
-     *
-     * @return string
-     */
-    public function DeleteLink()
-    {
-        return Controller::join_links(
-            Director::absoluteBaseURL(),
-            AdminRootController::admin_url(),
-            "assets/removefile/",
-            $this->ID
-        );
-    }
-
     /**
      * Get expected value of Filename tuple value. Will be used to trigger
      * a file move on draft stage.
diff --git a/src/ORM/CMSPreviewable.php b/src/ORM/CMSPreviewable.php
new file mode 100644
index 000000000..8f5a6d823
--- /dev/null
+++ b/src/ORM/CMSPreviewable.php
@@ -0,0 +1,40 @@
+<?php
+
+namespace SilverStripe\ORM;
+
+/**
+ * Interface to provide enough information about a record to make it previewable
+ * through the CMS. It uses the record database ID, its "frontend" and "backend"
+ * links to link up the edit form with its preview.
+ *
+ * Also used by {@link SilverStripeNavigator} to generate links -  both within
+ * the CMS preview, and as a frontend utility for logged-in CMS authors in
+ * custom themes (with the $SilverStripeNavigator template marker).
+ */
+interface CMSPreviewable
+{
+
+    /**
+     * Determine the preview link, if available, for this object.
+     * If no preview is available for this record, it may return null.
+     *
+     * @param string $action
+     * @return string Link to the end-user view for this record.
+     * Example: http://mysite.com/my-record
+     */
+    public function PreviewLink($action = null);
+
+    /**
+     * To determine preview mechanism (e.g. embedded / iframe)
+     *
+     * @return string
+     */
+    public function getMimeType();
+
+    /**
+     * @return string Link to the CMS-author view. Should point to a
+     * controller subclassing {@link LeftAndMain}. Example:
+     * http://mysite.com/admin/edit/6
+     */
+    public function CMSEditLink();
+}
diff --git a/src/ORM/Hierarchy/Hierarchy.php b/src/ORM/Hierarchy/Hierarchy.php
index 106900d7c..65d45589f 100644
--- a/src/ORM/Hierarchy/Hierarchy.php
+++ b/src/ORM/Hierarchy/Hierarchy.php
@@ -770,7 +770,7 @@ class Hierarchy extends DataExtension implements Resettable
      */
     public function showingCMSTree()
     {
-        if (!Controller::has_curr()) {
+        if (!Controller::has_curr() || !class_exists(LeftAndMain::class)) {
             return false;
         }
         $controller = Controller::curr();
diff --git a/src/ORM/Versioning/ChangeSetItem.php b/src/ORM/Versioning/ChangeSetItem.php
index 1ca17a38c..907223f0a 100644
--- a/src/ORM/Versioning/ChangeSetItem.php
+++ b/src/ORM/Versioning/ChangeSetItem.php
@@ -2,7 +2,7 @@
 
 namespace SilverStripe\ORM\Versioning;
 
-use SilverStripe\Admin\CMSPreviewable;
+use SilverStripe\ORM\CMSPreviewable;
 use SilverStripe\Assets\Thumbnail;
 use SilverStripe\Control\Controller;
 use SilverStripe\ORM\ArrayList;
diff --git a/src/Security/CMSSecurity.php b/src/Security/CMSSecurity.php
index 383627f49..55e3787a6 100644
--- a/src/Security/CMSSecurity.php
+++ b/src/Security/CMSSecurity.php
@@ -195,7 +195,7 @@ PHP
     public function success()
     {
         // Ensure member is properly logged in
-        if (!Member::currentUserID()) {
+        if (!Member::currentUserID() || !class_exists(AdminRootController::class)) {
             return $this->redirectToExternalLogin();
         }
 
diff --git a/src/Security/Group.php b/src/Security/Group.php
index 288fd6b71..5aaf2478c 100755
--- a/src/Security/Group.php
+++ b/src/Security/Group.php
@@ -144,10 +144,6 @@ class Group extends DataObject
             _t('Group.GroupReminder', 'If you choose a parent group, this group will take all it\'s roles')
         );
 
-        // Filter permissions
-        // TODO SecurityAdmin coupling, not easy to get to the form fields through GridFieldDetailForm
-        $permissionsField->setHiddenPermissions((array)Config::inst()->get('SilverStripe\\Admin\\SecurityAdmin', 'hidden_permissions'));
-
         if ($this->ID) {
             $group = $this;
             $config = GridFieldConfig_RelationEditor::create();
@@ -211,7 +207,10 @@ class Group extends DataObject
 
         // Only show the "Roles" tab if permissions are granted to edit them,
         // and at least one role exists
-        if (Permission::check('APPLY_ROLES') && DataObject::get('SilverStripe\\Security\\PermissionRole')) {
+        if (Permission::check('APPLY_ROLES') &&
+            PermissionRole::get()->count() &&
+            class_exists(SecurityAdmin::class)
+        ) {
             $fields->findOrMakeTab('Root.Roles', _t('SecurityAdmin.ROLES', 'Roles'));
             $fields->addFieldToTab(
                 'Root.Roles',
diff --git a/src/Security/Member.php b/src/Security/Member.php
index ed217be17..e7090a706 100644
--- a/src/Security/Member.php
+++ b/src/Security/Member.php
@@ -1437,6 +1437,11 @@ class Member extends DataObject implements TemplateGlobalProvider
      */
     public static function mapInCMSGroups($groups = null)
     {
+        // Check CMS module exists
+        if (!class_exists(LeftAndMain::class)) {
+            return ArrayList::create()->map();
+        }
+
         if (!$groups || $groups->Count() == 0) {
             $perms = array('ADMIN', 'CMS_ACCESS_AssetAdmin');