diff --git a/emacs/notmuch-address.el b/emacs/notmuch-address.el
index 2e8b8402..2bf762ba 100644
--- a/emacs/notmuch-address.el
+++ b/emacs/notmuch-address.el
@@ -38,9 +38,9 @@ line."
 (defvar notmuch-address-history nil)
 
 (defun notmuch-address-message-insinuate ()
-  (if (not (memq notmuch-address-message-alist-member message-completion-alist))
-      (setq message-completion-alist
-	    (push notmuch-address-message-alist-member message-completion-alist))))
+  (unless (memq notmuch-address-message-alist-member message-completion-alist)
+    (setq message-completion-alist
+	  (push notmuch-address-message-alist-member message-completion-alist))))
 
 (defun notmuch-address-options (original)
   (process-lines notmuch-address-command original))
diff --git a/emacs/notmuch-hello.el b/emacs/notmuch-hello.el
index bff95acc..ba48cd63 100644
--- a/emacs/notmuch-hello.el
+++ b/emacs/notmuch-hello.el
@@ -320,8 +320,8 @@ should be. Returns a cons cell `(tags-per-line width)'."
 
     ;; If the last line was not full (and hence did not include a
     ;; carriage return), insert one now.
-    (if (not (eq (% count tags-per-line) 0))
-	(widget-insert "\n"))
+    (unless (eq (% count tags-per-line) 0)
+      (widget-insert "\n"))
     found-target-pos))
 
 (defun notmuch-hello-goto-search ()
@@ -404,7 +404,7 @@ Complete list of currently available key bindings:
 
   ; Jump through a hoop to get this value from the deprecated variable
   ; name (`notmuch-folders') or from the default value.
-  (if (not notmuch-saved-searches)
+  (unless notmuch-saved-searches
     (setq notmuch-saved-searches (notmuch-saved-searches)))
 
   (if no-display
@@ -570,18 +570,18 @@ Complete list of currently available key bindings:
 	  (widget-insert "\n\n")
 	  (let ((start (point)))
 	    (setq found-target-pos (notmuch-hello-insert-tags alltags-alist widest target))
-	    (if (not final-target-pos)
-		(setq final-target-pos found-target-pos))
+	    (unless final-target-pos
+	      (setq final-target-pos found-target-pos))
 	    (indent-rigidly start (point) notmuch-hello-indent)))
 
 	(widget-insert "\n")
 
-	(if (not notmuch-show-all-tags-list)
-	    (widget-create 'push-button
-			   :notify (lambda (widget &rest ignore)
-				     (setq notmuch-show-all-tags-list t)
-				     (notmuch-hello-update))
-			   "Show all tags")))
+	(unless notmuch-show-all-tags-list
+	  (widget-create 'push-button
+			 :notify (lambda (widget &rest ignore)
+				   (setq notmuch-show-all-tags-list t)
+				   (notmuch-hello-update))
+			 "Show all tags")))
 
       (let ((start (point)))
 	(widget-insert "\n\n")
diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
index fc134627..92d3811c 100644
--- a/emacs/notmuch-show.el
+++ b/emacs/notmuch-show.el
@@ -662,8 +662,8 @@ current buffer, if possible."
   ;; part, so we make sure that we're down at the end.
   (goto-char (point-max))
   ;; Ensure that the part ends with a carriage return.
-  (if (not (bolp))
-      (insert "\n")))
+  (unless (bolp)
+    (insert "\n")))
 
 (defun notmuch-show-insert-body (msg body depth)
   "Insert the body BODY at depth DEPTH in the current thread."
@@ -743,8 +743,8 @@ current buffer, if possible."
     (setq body-start (point-marker))
     (notmuch-show-insert-body msg (plist-get msg :body) depth)
     ;; Ensure that the body ends with a newline.
-    (if (not (bolp))
-	(insert "\n"))
+    (unless (bolp)
+      (insert "\n"))
     (setq body-end (point-marker))
     (setq content-end (point-marker))
 
@@ -885,8 +885,8 @@ buffer."
       (run-hooks 'notmuch-show-hook))
 
     ;; Move straight to the first open message
-    (if (not (notmuch-show-message-visible-p))
-	(notmuch-show-next-open-message))
+    (unless (notmuch-show-message-visible-p)
+      (notmuch-show-next-open-message))
 
     ;; Set the header line to the subject of the first open message.
     (setq header-line-format (notmuch-show-strip-re (notmuch-show-get-subject)))
diff --git a/emacs/notmuch.el b/emacs/notmuch.el
index 3602361b..da75fafc 100644
--- a/emacs/notmuch.el
+++ b/emacs/notmuch.el
@@ -651,8 +651,8 @@ This function advances the next thread when finished."
 			(if notmuch-search-process-filter-data
 			    (insert (concat "Error: Unexpected output from notmuch search:\n" notmuch-search-process-filter-data)))
 			(insert "End of search results.")
-			(if (not (= exit-status 0))
-			    (insert (format " (process returned %d)" exit-status)))
+			(unless (= exit-status 0)
+			  (insert (format " (process returned %d)" exit-status)))
 			(insert "\n")
 			(if (and atbob
 				 (not (string= notmuch-search-target-thread "found")))
@@ -1022,8 +1022,8 @@ Invokes `notmuch-poll-script', \"notmuch new\", or does nothing
 depending on the value of `notmuch-poll-script'."
   (interactive)
   (if (stringp notmuch-poll-script)
-      (if (not (string= notmuch-poll-script ""))
-	  (call-process notmuch-poll-script nil nil))
+      (unless (string= notmuch-poll-script "")
+	(call-process notmuch-poll-script nil nil))
     (call-process notmuch-command nil nil nil "new")))
 
 (defun notmuch-search-poll-and-refresh-view ()