diff --git a/README.org b/README.org
index 9437b18..fa1e886 100644
--- a/README.org
+++ b/README.org
@@ -51,6 +51,8 @@ commands:
 
 - =devdocs-install=: Download and install (or reinstall) a document
   distributed by [[https://devdocs.io]].
+- =devdocs-ensure-docs-installed=: Check if documents are already
+  installed and install them if necessary.
 - =devdocs-delete=: Remove an installed document.
 - =devdocs-update-all=: Download and reinstall all installed documents
   for which a newer version is available.
diff --git a/devdocs.el b/devdocs.el
index ab5e646..8a2accb 100644
--- a/devdocs.el
+++ b/devdocs.el
@@ -275,6 +275,16 @@ already installed, reinstall it."
       (rename-file (file-name-as-directory temp) dest))
     (message "Document `%s' installed" slug)))
 
+;;;###autoload
+(defun devdocs-ensure-docs-installed (desired-docs)
+  "Ensure that every devdoc listed in DESIRED-DOCS is installed, without reinstalling."
+  (let ((installed (mapcar (lambda (installed-doc)
+                             (cdr (assoc 'slug installed-doc)))
+                           (devdocs--installed-docs))))
+    (dolist (desired-doc desired-docs)
+      (unless (cl-member desired-doc installed :test #'string=)
+        (devdocs-install desired-doc)))))
+
 ;;;###autoload
 (defun devdocs-update-all ()
   "Reinstall all documents with a new version available."