diff --git a/resources/sql/patches/legalpad-mailkey-populate.php b/resources/sql/patches/legalpad-mailkey-populate.php
new file mode 100644
index 0000000000..e754ab2757
--- /dev/null
+++ b/resources/sql/patches/legalpad-mailkey-populate.php
@@ -0,0 +1,25 @@
+<?php
+
+echo "Populating Legalpad Documents with mail keys...\n";
+$table = new LegalpadDocument();
+$table->openTransaction();
+
+foreach (new LiskMigrationIterator($table) as $document) {
+  $id = $document->getID();
+
+  echo "Document {$id}: ";
+  if (!$document->getMailKey()) {
+    queryfx(
+      $document->establishConnection('w'),
+      'UPDATE %T SET mailKey = %s WHERE id = %d',
+      $document->getTableName(),
+      Filesystem::readRandomCharacters(20),
+      $id);
+    echo "Generated Key\n";
+  } else {
+    echo "-\n";
+  }
+}
+
+$table->saveTransaction();
+echo "Done.\n";
diff --git a/resources/sql/patches/legalpad-mailkey.sql b/resources/sql/patches/legalpad-mailkey.sql
new file mode 100644
index 0000000000..b416f3518f
--- /dev/null
+++ b/resources/sql/patches/legalpad-mailkey.sql
@@ -0,0 +1,2 @@
+ALTER TABLE `{$NAMESPACE}_legalpad`.legalpad_document
+  ADD mailKey VARCHAR(20) NOT NULL COLLATE utf8_bin;
diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index b9478aab7d..3baf4ec98e 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -644,6 +644,8 @@ phutil_register_library_map(array(
     'LegalpadDocumentSearchEngine' => 'applications/legalpad/query/LegalpadDocumentSearchEngine.php',
     'LegalpadDocumentSignature' => 'applications/legalpad/storage/LegalpadDocumentSignature.php',
     'LegalpadDocumentViewController' => 'applications/legalpad/controller/LegalpadDocumentViewController.php',
+    'LegalpadMockMailReceiver' => 'applications/legalpad/mail/LegalpadMockMailReceiver.php',
+    'LegalpadReplyHandler' => 'applications/legalpad/mail/LegalpadReplyHandler.php',
     'LegalpadTransaction' => 'applications/legalpad/storage/LegalpadTransaction.php',
     'LegalpadTransactionComment' => 'applications/legalpad/storage/LegalpadTransactionComment.php',
     'LegalpadTransactionQuery' => 'applications/legalpad/query/LegalpadTransactionQuery.php',
@@ -1169,6 +1171,7 @@ phutil_register_library_map(array(
     'PhabricatorJavelinLinter' => 'infrastructure/lint/linter/PhabricatorJavelinLinter.php',
     'PhabricatorJumpNavHandler' => 'applications/search/engine/PhabricatorJumpNavHandler.php',
     'PhabricatorKeyValueDatabaseCache' => 'applications/cache/PhabricatorKeyValueDatabaseCache.php',
+    'PhabricatorLegalpadConfigOptions' => 'applications/legalpad/config/PhabricatorLegalpadConfigOptions.php',
     'PhabricatorLintEngine' => 'infrastructure/lint/PhabricatorLintEngine.php',
     'PhabricatorLipsumArtist' => 'applications/lipsum/image/PhabricatorLipsumArtist.php',
     'PhabricatorLipsumGenerateWorkflow' => 'applications/lipsum/management/PhabricatorLipsumGenerateWorkflow.php',
@@ -2572,6 +2575,8 @@ phutil_register_library_map(array(
     'LegalpadDocumentSearchEngine' => 'PhabricatorApplicationSearchEngine',
     'LegalpadDocumentSignature' => 'LegalpadDAO',
     'LegalpadDocumentViewController' => 'LegalpadController',
+    'LegalpadMockMailReceiver' => 'PhabricatorObjectMailReceiver',
+    'LegalpadReplyHandler' => 'PhabricatorMailReplyHandler',
     'LegalpadTransaction' => 'PhabricatorApplicationTransaction',
     'LegalpadTransactionComment' => 'PhabricatorApplicationTransactionComment',
     'LegalpadTransactionQuery' => 'PhabricatorApplicationTransactionQuery',
@@ -3120,6 +3125,7 @@ phutil_register_library_map(array(
     'PhabricatorInlineSummaryView' => 'AphrontView',
     'PhabricatorJavelinLinter' => 'ArcanistLinter',
     'PhabricatorKeyValueDatabaseCache' => 'PhutilKeyValueCache',
+    'PhabricatorLegalpadConfigOptions' => 'PhabricatorApplicationConfigOptions',
     'PhabricatorLintEngine' => 'PhutilLintEngine',
     'PhabricatorLipsumGenerateWorkflow' => 'PhabricatorLipsumManagementWorkflow',
     'PhabricatorLipsumManagementWorkflow' => 'PhutilArgumentWorkflow',
diff --git a/src/applications/legalpad/application/PhabricatorApplicationLegalpad.php b/src/applications/legalpad/application/PhabricatorApplicationLegalpad.php
index ff141819e9..c10ebddbb3 100644
--- a/src/applications/legalpad/application/PhabricatorApplicationLegalpad.php
+++ b/src/applications/legalpad/application/PhabricatorApplicationLegalpad.php
@@ -40,6 +40,7 @@ final class PhabricatorApplicationLegalpad extends PhabricatorApplication {
 
   public function getRoutes() {
     return array(
+      '/L(?P<id>\d+)/' => 'LegalpadDocumentViewController',
       '/legalpad/' => array(
         '' => 'LegalpadDocumentListController',
         '(query/(?P<queryKey>[^/]+)/)?' => 'LegalpadDocumentListController',
diff --git a/src/applications/legalpad/config/PhabricatorLegalpadConfigOptions.php b/src/applications/legalpad/config/PhabricatorLegalpadConfigOptions.php
new file mode 100644
index 0000000000..11f675eda5
--- /dev/null
+++ b/src/applications/legalpad/config/PhabricatorLegalpadConfigOptions.php
@@ -0,0 +1,27 @@
+<?php
+
+/**
+ * @group legalpad
+ */
+final class PhabricatorLegalpadConfigOptions
+  extends PhabricatorApplicationConfigOptions {
+
+  public function getName() {
+    return pht('Legalpad');
+  }
+
+  public function getDescription() {
+    return pht('Configure Legalpad.');
+  }
+
+  public function getOptions() {
+    return array(
+      $this->newOption(
+        'metamta.legalpad.subject-prefix',
+        'string',
+        '[Legalpad]')
+        ->setDescription(pht('Subject prefix for Legalpad email.'))
+    );
+  }
+
+}
diff --git a/src/applications/legalpad/controller/LegalpadDocumentCommentController.php b/src/applications/legalpad/controller/LegalpadDocumentCommentController.php
index ca1e01ff17..a7b9efa66d 100644
--- a/src/applications/legalpad/controller/LegalpadDocumentCommentController.php
+++ b/src/applications/legalpad/controller/LegalpadDocumentCommentController.php
@@ -22,6 +22,7 @@ final class LegalpadDocumentCommentController extends LegalpadController {
     $document = id(new LegalpadDocumentQuery())
       ->setViewer($user)
       ->withIDs(array($this->id))
+      ->needDocumentBodies(true)
       ->executeOne();
 
     if (!$document) {
diff --git a/src/applications/legalpad/editor/LegalpadDocumentEditor.php b/src/applications/legalpad/editor/LegalpadDocumentEditor.php
index 89364aae64..d588eadc33 100644
--- a/src/applications/legalpad/editor/LegalpadDocumentEditor.php
+++ b/src/applications/legalpad/editor/LegalpadDocumentEditor.php
@@ -111,10 +111,65 @@ final class LegalpadDocumentEditor
     return parent::mergeTransactions($u, $v);
   }
 
+/* -(  Sending Mail  )------------------------------------------------------- */
+
   protected function supportsMail() {
-    return false;
+    return true;
   }
 
+  protected function buildReplyHandler(PhabricatorLiskDAO $object) {
+    return id(new LegalpadReplyHandler())
+      ->setMailReceiver($object);
+  }
+
+  protected function buildMailTemplate(PhabricatorLiskDAO $object) {
+    $id = $object->getID();
+    $phid = $object->getPHID();
+    $title = $object->getDocumentBody()->getTitle();
+
+    return id(new PhabricatorMetaMTAMail())
+      ->setSubject("L{$id}: {$title}")
+      ->addHeader('Thread-Topic', "L{$id}: {$phid}");
+  }
+
+  protected function getMailTo(PhabricatorLiskDAO $object) {
+    return array(
+      $object->getCreatorPHID(),
+      $this->requireActor()->getPHID(),
+    );
+  }
+
+  protected function shouldImplyCC(
+    PhabricatorLiskDAO $object,
+    PhabricatorApplicationTransaction $xaction) {
+
+    switch ($xaction->getTransactionType()) {
+      case LegalpadTransactionType::TYPE_TEXT:
+      case LegalpadTransactionType::TYPE_TITLE:
+        return true;
+    }
+
+    return parent::shouldImplyCC($object, $xaction);
+  }
+
+  protected function buildMailBody(
+    PhabricatorLiskDAO $object,
+    array $xactions) {
+
+    $body = parent::buildMailBody($object, $xactions);
+
+    $body->addTextSection(
+      pht('DOCUMENT DETAIL'),
+      PhabricatorEnv::getProductionURI('/L'.$object->getID()));
+
+    return $body;
+  }
+
+  protected function getMailSubjectPrefix() {
+    return PhabricatorEnv::getEnvConfig('metamta.legalpad.subject-prefix');
+  }
+
+
   protected function supportsFeed() {
     return false;
   }
diff --git a/src/applications/legalpad/mail/LegalpadMockMailReceiver.php b/src/applications/legalpad/mail/LegalpadMockMailReceiver.php
new file mode 100644
index 0000000000..e6739049a9
--- /dev/null
+++ b/src/applications/legalpad/mail/LegalpadMockMailReceiver.php
@@ -0,0 +1,38 @@
+<?php
+
+final class LegalpadMockMailReceiver extends PhabricatorObjectMailReceiver {
+
+  public function isEnabled() {
+    $app_class = 'PhabricatorApplicationLegalpad';
+    return PhabricatorApplication::isClassInstalled($app_class);
+  }
+
+  protected function getObjectPattern() {
+    return 'L[1-9]\d*';
+  }
+
+  protected function loadObject($pattern, PhabricatorUser $viewer) {
+    $id = (int)trim($pattern, 'L');
+
+    return id(new LegalpadDocumentQuery())
+      ->setViewer($viewer)
+      ->withIDs(array($id))
+      ->needDocumentBodies(true)
+      ->executeOne();
+  }
+
+  protected function processReceivedObjectMail(
+    PhabricatorMetaMTAReceivedMail $mail,
+    PhabricatorLiskDAO $object,
+    PhabricatorUser $sender) {
+
+    $handler = id(new LegalpadReplyHandler())
+      ->setMailReceiver($object)
+      ->setActor($sender)
+      ->setExcludeMailRecipientPHIDs(
+        $mail->loadExcludeMailRecipientPHIDs());
+
+    return $handler->processEmail($mail);
+  }
+
+}
diff --git a/src/applications/legalpad/mail/LegalpadReplyHandler.php b/src/applications/legalpad/mail/LegalpadReplyHandler.php
new file mode 100644
index 0000000000..30befc3316
--- /dev/null
+++ b/src/applications/legalpad/mail/LegalpadReplyHandler.php
@@ -0,0 +1,99 @@
+<?php
+
+/**
+ * @group legalpad
+ */
+final class LegalpadReplyHandler extends PhabricatorMailReplyHandler {
+
+  public function validateMailReceiver($mail_receiver) {
+    if (!($mail_receiver instanceof LegalpadDocument)) {
+      throw new Exception("Mail receiver is not a LegalpadDocument!");
+    }
+  }
+
+  public function getPrivateReplyHandlerEmailAddress(
+    PhabricatorObjectHandle $handle) {
+    return $this->getDefaultPrivateReplyHandlerEmailAddress($handle, 'L');
+  }
+
+  public function getPublicReplyHandlerEmailAddress() {
+    return $this->getDefaultPublicReplyHandlerEmailAddress('L');
+  }
+
+  public function getReplyHandlerDomain() {
+    return PhabricatorEnv::getEnvConfig(
+      'metamta.reply-handler-domain');
+  }
+
+  public function getReplyHandlerInstructions() {
+    if ($this->supportsReplies()) {
+      return 'Reply to comment or !unsubscribe.';
+    } else {
+      return null;
+    }
+  }
+
+  protected function receiveEmail(PhabricatorMetaMTAReceivedMail $mail) {
+    $actor = $this->getActor();
+    $document = $this->getMailReceiver();
+
+    $body = $mail->getCleanTextBody();
+    $body = trim($body);
+    $body = $this->enhanceBodyWithAttachments($body, $mail->getAttachments());
+
+    $content_source = PhabricatorContentSource::newForSource(
+      PhabricatorContentSource::SOURCE_EMAIL,
+      array(
+        'id' => $mail->getID(),
+      ));
+
+    $lines = explode("\n", trim($body));
+    $first_line = head($lines);
+
+    $xactions = array();
+    $command = null;
+    $matches = null;
+    if (preg_match('/^!(\w+)/', $first_line, $matches)) {
+      $lines = array_slice($lines, 1);
+      $body = implode("\n", $lines);
+      $body = trim($body);
+
+      $command = $matches[1];
+    }
+
+    switch ($command) {
+      case 'unsubscribe':
+        $xaction = id(new LegalpadTransaction())
+          ->setTransactionType(PhabricatorTransactions::TYPE_SUBSCRIBERS)
+          ->setNewValue(array('-' => array($actor->getPHID())));
+        $xactions[] = $xaction;
+        break;
+    }
+
+    $xactions[] = id(new LegalpadTransaction())
+      ->setTransactionType(PhabricatorTransactions::TYPE_COMMENT)
+      ->attachComment(
+        id(new LegalpadTransactionComment())
+        ->setDocumentID($document->getID())
+        ->setLineNumber(0)
+        ->setLineLength(0)
+        ->setContent($body));
+
+    $editor = id(new LegalpadDocumentEditor())
+      ->setActor($actor)
+      ->setContentSource($content_source)
+      ->setContinueOnNoEffect(true)
+      ->setIsPreview(false);
+
+    try {
+      $xactions = $editor->applyTransactions($document, $xactions);
+    } catch (PhabricatorApplicationTransactionNoEffectException $ex) {
+      // just do nothing, though unclear why you're sending a blank email
+      return true;
+    }
+
+    $head_xaction = head($xactions);
+    return $head_xaction->getID();
+  }
+
+}
diff --git a/src/applications/legalpad/storage/LegalpadDocument.php b/src/applications/legalpad/storage/LegalpadDocument.php
index c72e7e853f..98b1714eb6 100644
--- a/src/applications/legalpad/storage/LegalpadDocument.php
+++ b/src/applications/legalpad/storage/LegalpadDocument.php
@@ -15,6 +15,7 @@ final class LegalpadDocument extends LegalpadDAO
   protected $documentBodyPHID;
   protected $viewPolicy;
   protected $editPolicy;
+  protected $mailKey;
 
   private $documentBody;
   private $contributors;
@@ -58,6 +59,13 @@ final class LegalpadDocument extends LegalpadDAO
     return $this;
   }
 
+  public function save() {
+    if (!$this->getMailKey()) {
+      $this->setMailKey(Filesystem::readRandomCharacters(20));
+    }
+    return parent::save();
+  }
+
 /* -(  PhabricatorSubscribableInterface Implementation  )-------------------- */
 
   public function isAutomaticallySubscribed($phid) {
diff --git a/src/applications/phid/handle/PhabricatorObjectHandleData.php b/src/applications/phid/handle/PhabricatorObjectHandleData.php
index f1572bb9a7..80db253653 100644
--- a/src/applications/phid/handle/PhabricatorObjectHandleData.php
+++ b/src/applications/phid/handle/PhabricatorObjectHandleData.php
@@ -213,7 +213,7 @@ final class PhabricatorObjectHandleData {
 
       case PhabricatorPHIDConstants::PHID_TYPE_LEGD:
         $legds = id(new LegalpadDocumentQuery())
-          ->needDocumentBody(true)
+          ->needDocumentBodies(true)
           ->withPHIDs($phids)
           ->setViewer($this->viewer)
           ->execute();
diff --git a/src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php b/src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php
index 9c6bdb8027..44adcaf273 100644
--- a/src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php
+++ b/src/infrastructure/storage/patch/PhabricatorBuiltinPatchList.php
@@ -1414,6 +1414,14 @@ final class PhabricatorBuiltinPatchList extends PhabricatorSQLPatchList {
         'type' => 'sql',
         'name' => $this->getPatchPath('20130701.conduitlog.sql'),
       ),
+      'legalpad-mailkey.sql' => array(
+        'type'    => 'sql',
+        'name'    => $this->getPatchPath('legalpad-mailkey.sql'),
+      ),
+      'legalpad-mailkey-populate.php' => array(
+        'type'    => 'php',
+        'name'    => $this->getPatchPath('legalpad-mailkey-populate.php'),
+      ),
     );
   }
 }