diff --git a/doc/libpkgconf-client.rst b/doc/libpkgconf-client.rst
new file mode 100644
index 0000000..6143430
--- /dev/null
+++ b/doc/libpkgconf-client.rst
@@ -0,0 +1,78 @@
+
+libpkgconf `client` module
+==========================
+
+The libpkgconf `client` module implements the `pkgconf_client_t` "client" object.
+Client objects store all necessary state for libpkgconf allowing for multiple instances to run
+in parallel.
+
+Client objects are not thread safe, in other words, a client object should not be shared across
+thread boundaries.
+
+.. c:function:: void pkgconf_client_init(pkgconf_client_t *client, pkgconf_error_handler_func_t error_handler)
+
+   Initialise a pkgconf client object.
+
+   :param pkgconf_client_t* client: The client to initialise.
+   :param pkgconf_error_handler_func_t error_handler: An optional error handler to use for logging errors.
+   :return: nothing
+
+.. c:function:: pkgconf_client_t* pkgconf_client_new(pkgconf_error_handler_func_t error_handler)
+
+   Allocate and initialise a pkgconf client object.
+
+   :param pkgconf_error_handler_func_t error_handler: An optional error handler to use for logging errors.
+   :return: A pkgconf client object.
+   :rtype: pkgconf_client_t*
+
+.. c:function:: void pkgconf_client_deinit(pkgconf_client_t *client)
+
+   Release resources belonging to a pkgconf client object.
+
+   :param pkgconf_client_t* client: The client to deinitialise.
+   :return: nothing
+
+.. c:function:: void pkgconf_client_free(pkgconf_client_t *client)
+
+   Release resources belonging to a pkgconf client object and then free the client object itself.
+
+   :param pkgconf_client_t* client: The client to deinitialise and free.
+   :return: nothing
+
+.. c:function:: const char *pkgconf_client_get_sysroot_dir(const pkgconf_client_t *client)
+
+   Retrieves the client's sysroot directory (if any).
+
+   :param pkgconf_client_t* client: The client object being accessed.
+   :return: A string containing the sysroot directory or NULL.
+   :rtype: const char *
+
+.. c:function:: void pkgconf_client_set_sysroot_dir(pkgconf_client_t *client, const char *sysroot_dir)
+
+   Sets or clears the sysroot directory on a client object.  Any previous sysroot directory setting is
+   automatically released if one was previously set.
+
+   Additionally, the global tuple ``$(pc_sysrootdir)`` is set as appropriate based on the new setting.
+
+   :param pkgconf_client_t* client: The client object being modified.
+   :param char* sysroot_dir: The sysroot directory to set or NULL to unset.
+   :return: nothing
+
+.. c:function:: const char *pkgconf_client_get_buildroot_dir(const pkgconf_client_t *client)
+
+   Retrieves the client's buildroot directory (if any).
+
+   :param pkgconf_client_t* client: The client object being accessed.
+   :return: A string containing the buildroot directory or NULL.
+   :rtype: const char *
+
+.. c:function:: void pkgconf_client_set_buildroot_dir(pkgconf_client_t *client, const char *buildroot_dir)
+
+   Sets or clears the buildroot directory on a client object.  Any previous buildroot directory setting is
+   automatically released if one was previously set.
+
+   Additionally, the global tuple ``$(pc_top_builddir)`` is set as appropriate based on the new setting.
+
+   :param pkgconf_client_t* client: The client object being modified.
+   :param char* buildroot_dir: The buildroot directory to set or NULL to unset.
+   :return: nothing
diff --git a/doc/libpkgconf.rst b/doc/libpkgconf.rst
index 525694e..c14d774 100644
--- a/doc/libpkgconf.rst
+++ b/doc/libpkgconf.rst
@@ -1,2 +1,7 @@
 libpkgconf - an API for managing `pkg-config` modules
 =====================================================
+
+.. toctree::
+   :maxdepth: 2
+
+   libpkgconf-client
diff --git a/libpkgconf/client.c b/libpkgconf/client.c
index f493bdf..17877a7 100644
--- a/libpkgconf/client.c
+++ b/libpkgconf/client.c
@@ -15,6 +15,31 @@
 
 #include <libpkgconf/libpkgconf.h>
 
+/*
+ * !doc
+ *
+ * libpkgconf `client` module
+ * ==========================
+ *
+ * The libpkgconf `client` module implements the `pkgconf_client_t` "client" object.
+ * Client objects store all necessary state for libpkgconf allowing for multiple instances to run
+ * in parallel.
+ *
+ * Client objects are not thread safe, in other words, a client object should not be shared across
+ * thread boundaries.
+ */
+
+/*
+ * !doc
+ *
+ * .. c:function:: void pkgconf_client_init(pkgconf_client_t *client, pkgconf_error_handler_func_t error_handler)
+ *
+ *    Initialise a pkgconf client object.
+ *
+ *    :param pkgconf_client_t* client: The client to initialise.
+ *    :param pkgconf_error_handler_func_t error_handler: An optional error handler to use for logging errors.
+ *    :return: nothing
+ */
 void
 pkgconf_client_init(pkgconf_client_t *client, pkgconf_error_handler_func_t error_handler)
 {
@@ -25,6 +50,17 @@ pkgconf_client_init(pkgconf_client_t *client, pkgconf_error_handler_func_t error
 	pkgconf_client_set_buildroot_dir(client, NULL);
 }
 
+/*
+ * !doc
+ *
+ * .. c:function:: pkgconf_client_t* pkgconf_client_new(pkgconf_error_handler_func_t error_handler)
+ *
+ *    Allocate and initialise a pkgconf client object.
+ *
+ *    :param pkgconf_error_handler_func_t error_handler: An optional error handler to use for logging errors.
+ *    :return: A pkgconf client object.
+ *    :rtype: pkgconf_client_t*
+ */
 pkgconf_client_t *
 pkgconf_client_new(pkgconf_error_handler_func_t error_handler)
 {
@@ -33,6 +69,16 @@ pkgconf_client_new(pkgconf_error_handler_func_t error_handler)
 	return out;
 }
 
+/*
+ * !doc
+ *
+ * .. c:function:: void pkgconf_client_deinit(pkgconf_client_t *client)
+ *
+ *    Release resources belonging to a pkgconf client object.
+ *
+ *    :param pkgconf_client_t* client: The client to deinitialise.
+ *    :return: nothing
+ */
 void
 pkgconf_client_deinit(pkgconf_client_t *client)
 {
@@ -47,6 +93,16 @@ pkgconf_client_deinit(pkgconf_client_t *client)
 	pkgconf_cache_free(client);
 }
 
+/*
+ * !doc
+ *
+ * .. c:function:: void pkgconf_client_free(pkgconf_client_t *client)
+ *
+ *    Release resources belonging to a pkgconf client object and then free the client object itself.
+ *
+ *    :param pkgconf_client_t* client: The client to deinitialise and free.
+ *    :return: nothing
+ */
 void
 pkgconf_client_free(pkgconf_client_t *client)
 {
@@ -54,12 +110,37 @@ pkgconf_client_free(pkgconf_client_t *client)
 	free(client);
 }
 
+/*
+ * !doc
+ *
+ * .. c:function:: const char *pkgconf_client_get_sysroot_dir(const pkgconf_client_t *client)
+ *
+ *    Retrieves the client's sysroot directory (if any).
+ *
+ *    :param pkgconf_client_t* client: The client object being accessed.
+ *    :return: A string containing the sysroot directory or NULL.
+ *    :rtype: const char *
+ */
 const char *
 pkgconf_client_get_sysroot_dir(const pkgconf_client_t *client)
 {
 	return client->sysroot_dir;
 }
 
+/*
+ * !doc
+ *
+ * .. c:function:: void pkgconf_client_set_sysroot_dir(pkgconf_client_t *client, const char *sysroot_dir)
+ *
+ *    Sets or clears the sysroot directory on a client object.  Any previous sysroot directory setting is
+ *    automatically released if one was previously set.
+ *
+ *    Additionally, the global tuple ``$(pc_sysrootdir)`` is set as appropriate based on the new setting.
+ *
+ *    :param pkgconf_client_t* client: The client object being modified.
+ *    :param char* sysroot_dir: The sysroot directory to set or NULL to unset.
+ *    :return: nothing
+ */
 void
 pkgconf_client_set_sysroot_dir(pkgconf_client_t *client, const char *sysroot_dir)
 {
@@ -71,12 +152,37 @@ pkgconf_client_set_sysroot_dir(pkgconf_client_t *client, const char *sysroot_dir
 	pkgconf_tuple_add_global(client, "pc_sysrootdir", client->sysroot_dir != NULL ? client->sysroot_dir : "/");
 }
 
+/*
+ * !doc
+ *
+ * .. c:function:: const char *pkgconf_client_get_buildroot_dir(const pkgconf_client_t *client)
+ *
+ *    Retrieves the client's buildroot directory (if any).
+ *
+ *    :param pkgconf_client_t* client: The client object being accessed.
+ *    :return: A string containing the buildroot directory or NULL.
+ *    :rtype: const char *
+ */
 const char *
 pkgconf_client_get_buildroot_dir(const pkgconf_client_t *client)
 {
 	return client->buildroot_dir;
 }
 
+/*
+ * !doc
+ *
+ * .. c:function:: void pkgconf_client_set_buildroot_dir(pkgconf_client_t *client, const char *buildroot_dir)
+ *
+ *    Sets or clears the buildroot directory on a client object.  Any previous buildroot directory setting is
+ *    automatically released if one was previously set.
+ *
+ *    Additionally, the global tuple ``$(pc_top_builddir)`` is set as appropriate based on the new setting.
+ *
+ *    :param pkgconf_client_t* client: The client object being modified.
+ *    :param char* buildroot_dir: The buildroot directory to set or NULL to unset.
+ *    :return: nothing
+ */
 void
 pkgconf_client_set_buildroot_dir(pkgconf_client_t *client, const char *buildroot_dir)
 {