diff --git a/docs/index.rst b/docs/index.rst
index a0b96729..d1401fa6 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -13,6 +13,7 @@ Contents:
 
    intro.rst
    lang.rst
+   libs.rst
 
 Indices and tables
 ==================
diff --git a/docs/lang.rst b/docs/lang.rst
index 220addb2..ec149d98 100644
--- a/docs/lang.rst
+++ b/docs/lang.rst
@@ -1,106 +1,7 @@
 Language
 ========
 
-The language provided by picrin.
-
-Libraries
----------
-
-- ``(scheme base)``
-- ``(scheme write)``
-- ``(scheme cxr)``
-- ``(scheme file)``
-- ``(scheme inexact)``
-- ``(scheme time)``
-- ``(scheme process-context)``
-- ``(scheme load)``
-- ``(scheme lazy)``
-- ``(picrin macro)``
-
-  - ``define-macro``
-  - ``gensym``
-  - ``macroexpand``
-
-  Old-fashioned macro.
-
-  - ``make-syntactic-closure``
-  - ``identifier?``
-  - ``identifier=?``
-
-  Syntactic closures.
-
-  - ``er-macro-transformer``
-  - ``ir-macro-transformer``
-
-  Explicit renaming macro family.
-
-- ``(picrin regexp)``
-
-  - ``(regexp? obj)``
-  - ``(regexp ptrn [flags])``
-
-  Compiles pattern string into a regexp object. A string ``flags`` may contain any of #\g, #\i, #\m.
-
-  - ``(regexp-match re input)``
-
-  Returns two values: a list of match strings, and a list of match indeces.
-
-  - ``(regexp-replace re input txt)``
-  - ``(regexp-split re input)``
-
-- ``(picrin control)``
-
-  - ``(reset h)``
-  - ``(shift k)``
-
-  Delimited control operators.
-
-- ``(picrin dictionary)``
-
-  Symbol to Object table. Internally it is implemented on hash-table.
-
-  Note that dictionary is not a weak map; if you are going to make a highly memory-consuming program with dictionaries, you should know that dictionaries keep their bound objects and never let them free until you explicitly deletes bindings.
-
-  - ``(dictionary)``
-
-    Returns a newly allocated empty dictionary. In the future, it is planned to extend this function to take optional arguments for initial key/values.
-
-  - ``(dictionary? obj)``
-
-    Returns ``#t`` if obj is a dictionary.
-
-  - ``(dictionary-ref dict key)``
-
-    Look up dictionary dict for a value associated with symbol key. If no object is associated with key, it will raise an error.
-
-  - ``(dictionary-set! dict key obj)``
-
-    If there is no value already associated with key, this function newly creates a binding of key with obj. Otherwise, updates the existing binding with given obj.
-
-  - ``(dictionary-delete dict key)``
-
-    Deletes the binding associated with key from dict. If no binding on dict is associated with key, an error will be raised.
-
-
-  - ``(dictionary-size dict)``
-
-    Returns the number of registered elements in dict.
-
-- ``(picrin user)``
-
-  When you start the REPL, you are dropped into here.
-
-- ``(srfi 1)``
-
-  List manipulation library.
-
-- ``(srfi 26)``
-
-  Cut/cute macros.
-
-- ``(srfi 95)``
-
-  Sorting and Marging.
+Picrin's core language is the R7RS scheme with some powerful extensions. Please visit http://r7rs.org/ for the information of R7RS's design and underlying thoughts.
 
 The REPL
 --------
diff --git a/docs/libs.rst b/docs/libs.rst
new file mode 100644
index 00000000..79457e17
--- /dev/null
+++ b/docs/libs.rst
@@ -0,0 +1,116 @@
+Libraries
+=========
+
+Picrin's all built-in libraries are described below.
+
+Scheme standard libraries
+-------------------------
+
+- (scheme write)
+- (scheme cxr)
+- (scheme file)
+- (scheme inexact)
+- (scheme time)
+- (scheme process-context)
+- (scheme load)
+- (scheme lazy)
+
+SRFI libraries
+--------------
+
+- (srfi 1)
+
+  List manipulation library.
+
+- (srfi 26)
+
+  Cut/cute macros.
+
+- (srfi 95)
+
+  Sorting and Marging.
+
+
+Macros
+------
+
+(picrin macro)
+^^^^^^^^^^^^^^
+
+- define-macro
+- gensym
+- macroexpand
+
+Old-fashioned macro.
+
+- make-syntactic-closure
+- identifier?
+- identifier=?
+
+Syntactic closures.
+
+- er-macro-transformer
+- ir-macro-transformer
+
+Explicit renaming macro family.
+
+(picrin regexp)
+^^^^^^^^^^^^^^^
+
+- (regexp? obj)
+- (regexp ptrn [flags])
+
+Compiles pattern string into a regexp object. A string flags may contain any of #\g, #\i, #\m.
+
+- (regexp-match re input)
+
+Returns two values: a list of match strings, and a list of match indeces.
+
+- (regexp-replace re input txt)
+- (regexp-split re input)
+
+(picrin control)
+^^^^^^^^^^^^^^^^
+
+- (reset h)
+- (shift k)
+
+Delimited control operators.
+
+(picrin dictionary)
+^^^^^^^^^^^^^^^^^^^
+
+Symbol to Object table. Internally it is implemented on hash-table.
+
+Note that dictionary is not a weak map; if you are going to make a highly memory-consuming program with dictionaries, you should know that dictionaries keep their bound objects and never let them free until you explicitly deletes bindings.
+
+- (dictionary)
+
+  Returns a newly allocated empty dictionary. In the future, it is planned to extend this function to take optional arguments for initial key/values.
+
+- (dictionary? obj)
+
+  Returns #t if obj is a dictionary.
+
+- (dictionary-ref dict key)
+
+  Look up dictionary dict for a value associated with symbol key. If no object is associated with key, it will raise an error.
+
+- (dictionary-set! dict key obj)
+
+  If there is no value already associated with key, this function newly creates a binding of key with obj. Otherwise, updates the existing binding with given obj.
+
+- (dictionary-delete dict key)
+
+  Deletes the binding associated with key from dict. If no binding on dict is associated with key, an error will be raised.
+
+
+- (dictionary-size dict)
+
+  Returns the number of registered elements in dict.
+
+(picrin user)
+^^^^^^^^^^^^^
+
+When you start the REPL, you are dropped into here.
+