diff --git a/src/common/backtrace.c b/src/common/backtrace.c
index 94de1eb5ee81b5d3d725c9f1fbc62f9b9fdb85af..f7b5dc21b7a5523d027944e04e9a666e59e8dd47 100644
--- a/src/common/backtrace.c
+++ b/src/common/backtrace.c
@@ -1,6 +1,13 @@
 /* Copyright (c) 2013-2015, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
+/**
+ * \file backtrace.c
+ *
+ * \brief Functions to produce backtraces on bugs, crashes, or assertion
+ * failures.
+ */
+
 #define __USE_GNU
 #define _GNU_SOURCE 1
 
diff --git a/src/common/compat_pthreads.c b/src/common/compat_pthreads.c
index b1d87d38f21910972ff610fe9940f4674b04c5df..b59f0970a564eb75cab7f2dea8f9cd0606e9e7af 100644
--- a/src/common/compat_pthreads.c
+++ b/src/common/compat_pthreads.c
@@ -3,6 +3,13 @@
  * Copyright (c) 2007-2015, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
+/**
+ * \file compat_pthreads.c
+ *
+ * \brief Implementation for the pthreads-based multithreading backend
+ * functions.
+ */
+
 #define _GNU_SOURCE
 
 #include "orconfig.h"
diff --git a/src/common/compat_threads.c b/src/common/compat_threads.c
index 85ad73757477b461ddb2909b507c1086dbe04d86..848b10a023a8c3ffe3b52ff1fecf8d1372f91790 100644
--- a/src/common/compat_threads.c
+++ b/src/common/compat_threads.c
@@ -3,6 +3,14 @@
  * Copyright (c) 2007-2015, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
+/**
+ * \file compat_threads.c
+ *
+ * \brief Cross-platform threading and inter-thread communication logic.
+ *  (Platform-specific parts are written in the other compat_*threads
+ *  modules.)
+ */
+
 #define _GNU_SOURCE
 
 #include "orconfig.h"
diff --git a/src/common/compat_winthreads.c b/src/common/compat_winthreads.c
index 9a87daa871b9499f3c241bcc0b515ea13b710f50..ba0b6419080f6a0d72691cf2a836c154070e92c8 100644
--- a/src/common/compat_winthreads.c
+++ b/src/common/compat_winthreads.c
@@ -3,6 +3,13 @@
  * Copyright (c) 2007-2015, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
+/**
+ * \file compat_winthreads.c
+ *
+ * \brief Implementation for the windows-based multithreading backend
+ * functions.
+ */
+
 #ifdef _WIN32
 
 #include "compat.h"
diff --git a/src/common/crypto_curve25519.c b/src/common/crypto_curve25519.c
index 2002483265829a079027e60a056b01ed840eaacb..47a93bf275f7df0ca497cb0ced7a934ab1aa46ae 100644
--- a/src/common/crypto_curve25519.c
+++ b/src/common/crypto_curve25519.c
@@ -1,7 +1,11 @@
 /* Copyright (c) 2012-2015, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
-/* Wrapper code for a curve25519 implementation. */
+/**
+ * \file crypto_curve25519.c
+ *
+ * \brief Wrapper code for a curve25519 implementation.
+ */
 
 #define CRYPTO_CURVE25519_PRIVATE
 #include "orconfig.h"
diff --git a/src/common/crypto_ed25519.c b/src/common/crypto_ed25519.c
index 9df665f66a6ea0bbe034240675a1ffdd2e18945f..3409b7fbe110c1a5dbf7385ae6458a5426f9d543 100644
--- a/src/common/crypto_ed25519.c
+++ b/src/common/crypto_ed25519.c
@@ -1,7 +1,11 @@
 /* Copyright (c) 2013-2015, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
-/* Wrapper code for an ed25519 implementation. */
+/**
+ * \file crypto_ed25519.c
+ *
+ * \brief Wrapper code for an ed25519 implementation.
+ */
 
 #include "orconfig.h"
 #ifdef HAVE_SYS_STAT_H
diff --git a/src/common/crypto_format.c b/src/common/crypto_format.c
index d4ecd5b19221a84393a56500a3224da8eff73e9f..422ebb5926ef9b2621a3355a6270188dcc116b5d 100644
--- a/src/common/crypto_format.c
+++ b/src/common/crypto_format.c
@@ -4,7 +4,11 @@
  * Copyright (c) 2007-2015, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
-/* Formatting and parsing code for crypto-related data structures. */
+/**
+ * \file crypto_format.c
+ *
+ * \brief Formatting and parsing code for crypto-related data structures.
+ */
 
 #include "orconfig.h"
 #ifdef HAVE_SYS_STAT_H
diff --git a/src/common/crypto_pwbox.c b/src/common/crypto_pwbox.c
index b866c7ef391f3d7ea834395d5f74a476c5da113a..819dc0c39d4a7250de0a133de971d25d65e27a9a 100644
--- a/src/common/crypto_pwbox.c
+++ b/src/common/crypto_pwbox.c
@@ -1,3 +1,12 @@
+/* Copyright (c) 2014-2016, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file crypto_pwbox.c
+ *
+ * \brief Code for encrypting secrets in a password-protected form and saving
+ * them to disk.
+ */
 
 #include "crypto.h"
 #include "crypto_s2k.h"
diff --git a/src/common/crypto_s2k.c b/src/common/crypto_s2k.c
index 99f3b2ebbcaf3697fd4d5357e614556bfdec0915..6dd791e018427bb7e1c3574f9540ebcab125f19c 100644
--- a/src/common/crypto_s2k.c
+++ b/src/common/crypto_s2k.c
@@ -4,6 +4,12 @@
  * Copyright (c) 2007-2015, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
+/**
+ * \file crypto_s2k.c
+ *
+ * \brief Functions for deriving keys from human-readable passphrases.
+ */
+
 #define CRYPTO_S2K_PRIVATE
 
 #include "crypto.h"
diff --git a/src/common/util_format.c b/src/common/util_format.c
index 8d99138506e870fa89a779298427435619ea3b4d..476e098e0bfb1a9a0bc6036d1160a7265652d067 100644
--- a/src/common/util_format.c
+++ b/src/common/util_format.c
@@ -4,6 +4,13 @@
  * Copyright (c) 2007-2015, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
+/**
+ * \file util_format.c
+ *
+ * \brief Miscellaneous functions for encoding and decoding various things
+ *   in base{16,32,64}.
+ */
+
 #include "orconfig.h"
 #include "torlog.h"
 #include "util.h"
diff --git a/src/common/workqueue.c b/src/common/workqueue.c
index c467bdf43bc104dff55dc4d136ca9a383f5f2d29..0a38550de0b14fbc7621f01c78884d18b7ffd27c 100644
--- a/src/common/workqueue.c
+++ b/src/common/workqueue.c
@@ -1,6 +1,13 @@
 /* copyright (c) 2013-2015, The Tor Project, Inc. */
 /* See LICENSE for licensing information */
 
+/**
+ * \file workqueue.c
+ *
+ * \brief Implements worker threads, queues of work for them, and mechanisms
+ * for them to send answers back to the main thread.
+ */
+
 #include "orconfig.h"
 #include "compat.h"
 #include "compat_threads.h"