diff --git a/edit.html b/edit.html
index 950dfcad..da93b705 100644
--- a/edit.html
+++ b/edit.html
@@ -93,6 +93,7 @@
     <script src="edit/linter-csslint.js"></script>
     <script src="edit/linter-stylelint.js"></script>
     <script src="edit/linter-meta.js"></script>
+    <script src="edit/linter-help-dialog.js"></script>
     <script src="edit/linter-report.js"></script>
 
     <script src="edit/editor-worker.js"></script>
diff --git a/edit/linter-help-dialog.js b/edit/linter-help-dialog.js
new file mode 100644
index 00000000..98c11903
--- /dev/null
+++ b/edit/linter-help-dialog.js
@@ -0,0 +1,56 @@
+/* global showHelp editorWorker */
+'use strict';
+
+function createLinterHelpDialog(getIssues) {
+  let csslintRules;
+  let preparing;
+  return {show};
+
+  function show() {
+    // FIXME: implement a linterChooser?
+    const linter = $('#editor.linter').value;
+    const baseUrl = linter === 'stylelint'
+      ? 'https://stylelint.io/user-guide/rules/'
+      // some CSSLint rules do not have a url
+      : 'https://github.com/CSSLint/csslint/issues/535';
+    let headerLink, template;
+    if (linter === 'csslint') {
+      headerLink = $createLink('https://github.com/CSSLint/csslint/wiki/Rules', 'CSSLint');
+      template = ({rule: ruleID}) => {
+        const rule = csslintRules.find(rule => rule.id === ruleID);
+        return rule &&
+          $create('li', [
+            $create('b', $createLink(rule.url || baseUrl, rule.name)),
+            $create('br'),
+            rule.desc,
+          ]);
+      };
+    } else {
+      headerLink = $createLink(baseUrl, 'stylelint');
+      template = ({rule}) =>
+        $create('li',
+          rule === 'CssSyntaxError' ? rule : $createLink(baseUrl + rule, rule));
+    }
+    const header = t('linterIssuesHelp', '\x01').split('\x01');
+    const activeRules = getIssues();
+    Promise.resolve(linter === 'csslint' && prepareCsslintRules())
+      .then(() =>
+        showHelp(t('linterIssues'),
+          $create([
+            header[0], headerLink, header[1],
+            $create('ul.rules', [...activeRules.values()].map(template)),
+          ])
+        )
+      );
+  }
+
+  function prepareCsslintRules() {
+    if (!preparing) {
+      preparing = editorWorker.getCsslintRules()
+        .then(rules => {
+          csslintRules = rules;
+        });
+    }
+    return preparing;
+  }
+}
diff --git a/edit/linter-report.js b/edit/linter-report.js
index eec4bd9c..4800223a 100644
--- a/edit/linter-report.js
+++ b/edit/linter-report.js
@@ -1,8 +1,9 @@
-/* global linter editors clipString */
+/* global linter editors clipString createLinterHelpDialog makeSectionVisible */
 'use strict';
 
 var linterReport = (() => { // eslint-disable-line no-var
   const cms = new Map();
+  const helpDialog = createLinterHelpDialog(getIssues);
 
   linter.onChange((annotationsNotSorted, annotations, cm) => {
     let table = cms.get(cm);
@@ -31,12 +32,22 @@ var linterReport = (() => { // eslint-disable-line no-var
   });
 
   document.addEventListener('DOMContentLoaded', () => {
-    $('#lint-help').addEventListener('click', showLintHelp);
+    $('#lint-help').addEventListener('click', helpDialog.show);
     $('#linter-settings').addEventListener('click', showLintConfig);
   }, {once: true});
 
   return {refresh};
 
+  function getIssues() {
+    const issues = new Set();
+    for (const table of cms.values()) {
+      for (const tr of table.trs) {
+        issues.add(tr.getAnnotation());
+      }
+    }
+    return issues;
+  }
+
   function findNextSibling(cms, cm) {
     let i = editors.indexOf(cm) + 1;
     while (i < editors.length) {
@@ -55,7 +66,13 @@ var linterReport = (() => { // eslint-disable-line no-var
     const table = $create('table', [caption, tbody]);
     const trs = [];
     let empty = true;
-    return {updateAnnotations, update, isEmpty, element: table};
+    return {
+      element: table,
+      trs,
+      updateAnnotations,
+      update,
+      isEmpty
+    };
 
     function isEmpty() {
       return empty;
@@ -112,7 +129,8 @@ var linterReport = (() => { // eslint-disable-line no-var
       ]);
       return {
         element: trElement,
-        update
+        update,
+        getAnnotation: () => anno
       };
 
       function update(_anno) {
@@ -135,7 +153,5 @@ var linterReport = (() => { // eslint-disable-line no-var
     cm.setSelection(anno.from);
   }
 
-  function showLintHelp() {}
-
   function showLintConfig() {}
 })();