diff --git a/IPython/nbformat/__init__.py b/IPython/nbformat/__init__.py
index e69de29..e6b1309 100644
--- a/IPython/nbformat/__init__.py
+++ b/IPython/nbformat/__init__.py
@@ -0,0 +1,143 @@
+"""The IPython notebook format
+
+Use this module to read or write notebook files as particular nbformat versions.
+"""
+
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
+
+from IPython.utils.log import get_logger
+
+from . import v1
+from . import v2
+from . import v3
+from . import v4
+
+versions = {
+    1: v1,
+    2: v2,
+    3: v3,
+    4: v4,
+}
+
+from .validator import validate, ValidationError
+from .converter import convert
+from . import reader
+
+from .v4 import (
+    nbformat as current_nbformat,
+    nbformat_minor as current_nbformat_minor,
+)
+
+class NBFormatError(ValueError):
+    pass
+
+# no-conversion singleton
+NO_CONVERT = object()
+
+def reads(s, as_version, **kwargs):
+    """Read a notebook from a string and return the NotebookNode object as the given version.
+    
+    The string can contain a notebook of any version.
+    The notebook will be returned `as_version`, converting, if necessary.
+
+    Notebook format errors will be logged.
+
+    Parameters
+    ----------
+    s : unicode
+        The raw unicode string to read the notebook from.
+    as_version : int
+        The version of the notebook format to return.
+        The notebook will be converted, if necessary.
+        Pass nbformat.NO_CONVERT to prevent conversion.
+
+    Returns
+    -------
+    nb : NotebookNode
+        The notebook that was read.
+    """
+    nb = reader.reads(s, **kwargs)
+    if as_version is not NO_CONVERT:
+        nb = convert(nb, as_version)
+    try:
+        validate(nb)
+    except ValidationError as e:
+        get_logger().error("Notebook JSON is invalid: %s", e)
+    return nb
+
+
+def writes(nb, version, **kwargs):
+    """Write a notebook to a string in a given format in the given nbformat version.
+
+    Any notebook format errors will be logged.
+
+    Parameters
+    ----------
+    nb : NotebookNode
+        The notebook to write.
+    version : int
+        The nbformat version to write.
+        If nb is not this version, it will be converted.
+        Pass nbformat.NO_CONVERT to prevent conversion.
+
+    Returns
+    -------
+    s : unicode
+        The notebook as a JSON string.
+    """
+    if version is not NO_CONVERT:
+        nb = convert(nb, version)
+    else:
+        version, _ = reader.get_version(nb)
+    try:
+        validate(nb)
+    except ValidationError as e:
+        get_logger().error("Notebook JSON is invalid: %s", e)
+    return versions[version].writes_json(nb, **kwargs)
+
+
+def read(fp, as_version, **kwargs):
+    """Read a notebook from a file as a NotebookNode of the given version.
+
+    The string can contain a notebook of any version.
+    The notebook will be returned `as_version`, converting, if necessary.
+
+    Notebook format errors will be logged.
+
+    Parameters
+    ----------
+    fp : file
+        Any file-like object with a read method.
+    as_version: int
+        The version of the notebook format to return.
+        The notebook will be converted, if necessary.
+        Pass nbformat.NO_CONVERT to prevent conversion.
+
+    Returns
+    -------
+    nb : NotebookNode
+        The notebook that was read.
+    """
+    return reads(fp.read(), as_version, **kwargs)
+
+
+def write(fp, nb, version, **kwargs):
+    """Write a notebook to a file in a given nbformat version.
+    
+    The file-like object must accept unicode input.
+    
+    Parameters
+    ----------
+    fp : file
+        Any file-like object with a write method that accepts unicode.
+    nb : NotebookNode
+        The notebook to write.
+    version : int
+        The nbformat version to write.
+        If nb is not this version, it will be converted.
+    """
+    s = writes(nb, version, **kwargs)
+    if isinstance(s, bytes):
+        s = s.decode('utf8')
+    return fp.write(s)
diff --git a/IPython/nbformat/convert.py b/IPython/nbformat/converter.py
similarity index 94%
rename from IPython/nbformat/convert.py
rename to IPython/nbformat/converter.py
index 5a2b86d..a2ea892 100644
--- a/IPython/nbformat/convert.py
+++ b/IPython/nbformat/converter.py
@@ -3,7 +3,8 @@
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
-from .reader import get_version, versions
+from . import versions
+from .reader import get_version
 
 
 def convert(nb, to_version):
@@ -24,7 +25,7 @@ def convert(nb, to_version):
     # Get input notebook version.
     (version, version_minor) = get_version(nb)
 
-    # Check if destination is current version, if so return contents
+    # Check if destination is target version, if so return contents
     if version == to_version:
         return nb
 
diff --git a/IPython/nbformat/current.py b/IPython/nbformat/current.py
index 0f796fd..2f5f832 100644
--- a/IPython/nbformat/current.py
+++ b/IPython/nbformat/current.py
@@ -17,8 +17,8 @@ from IPython.nbformat.v3 import (
 from IPython.nbformat import v3 as _v_latest
 
 from .reader import reads as reader_reads
-from .reader import versions
-from .convert import convert
+from . import versions
+from .converter import convert
 from .validator import validate, ValidationError
 
 from IPython.utils.log import get_logger
diff --git a/IPython/nbformat/reader.py b/IPython/nbformat/reader.py
index 158e071..20ddaef 100644
--- a/IPython/nbformat/reader.py
+++ b/IPython/nbformat/reader.py
@@ -5,19 +5,6 @@
 
 import json
 
-from . import v1
-from . import v2
-from . import v3
-from . import v4
-
-versions = {
-    1: v1,
-    2: v2,
-    3: v3,
-    4: v4,
-    }
-
-
 class NotJSONError(ValueError):
     pass
 
@@ -66,7 +53,7 @@ def reads(s, **kwargs):
     nb : NotebookNode
         The notebook that was read.
     """
-    from .current import NBFormatError
+    from . import versions, NBFormatError
     
     nb_dict = parse_json(s, **kwargs)
     (major, minor) = get_version(nb_dict)
diff --git a/IPython/nbformat/sign.py b/IPython/nbformat/sign.py
index 2005be1..17d9e1f 100644
--- a/IPython/nbformat/sign.py
+++ b/IPython/nbformat/sign.py
@@ -10,12 +10,13 @@ from hmac import HMAC
 import io
 import os
 
+from IPython.utils.io import atomic_writing
 from IPython.utils.py3compat import string_types, unicode_type, cast_bytes
 from IPython.utils.traitlets import Instance, Bytes, Enum, Any, Unicode, Bool
 from IPython.config import LoggingConfigurable, MultipleInstanceError
 from IPython.core.application import BaseIPythonApplication, base_flags
 
-from .current import read, write
+from . import read, write, NO_CONVERT
 
 try:
     # Python 3
@@ -278,14 +279,14 @@ class TrustNotebookApp(BaseIPythonApplication):
             self.log.error("Notebook missing: %s" % notebook_path)
             self.exit(1)
         with io.open(notebook_path, encoding='utf8') as f:
-            nb = read(f, 'json')
+            nb = read(f, NO_CONVERT)
         if self.notary.check_signature(nb):
             print("Notebook already signed: %s" % notebook_path)
         else:
             print("Signing notebook: %s" % notebook_path)
             self.notary.sign(nb)
-            with io.open(notebook_path, 'w', encoding='utf8') as f:
-                write(nb, f, 'json')
+            with atomic_writing(notebook_path) as f:
+                write(f, nb, NO_CONVERT)
     
     def generate_new_key(self):
         """Generate a new notebook signature key"""
diff --git a/IPython/nbformat/tests/test_current.py b/IPython/nbformat/tests/test_api.py
similarity index 71%
rename from IPython/nbformat/tests/test_current.py
rename to IPython/nbformat/tests/test_api.py
index 818447a..1fb1585 100644
--- a/IPython/nbformat/tests/test_current.py
+++ b/IPython/nbformat/tests/test_api.py
@@ -1,29 +1,25 @@
-"""
-Contains tests class for current.py
-"""
+"""Test the APIs at the top-level of nbformat"""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
-import io
 import json
-import tempfile
 
 from .base import TestsBase
 
 from ..reader import get_version
-from ..current import read, current_nbformat, validate, writes
+from IPython.nbformat import read, current_nbformat, writes
 
 
-class TestCurrent(TestsBase):
+class TestAPI(TestsBase):
 
     def test_read(self):
         """Can older notebooks be opened and automatically converted to the current 
         nbformat?"""
 
         # Open a version 2 notebook.
-        with self.fopen(u'test2.ipynb', u'r') as f:
-            nb = read(f)
+        with self.fopen(u'test2.ipynb', 'r') as f:
+            nb = read(f, as_version=current_nbformat)
 
         # Check that the notebook was upgraded to the latest version automatically.
         (major, minor) = get_version(nb)
@@ -33,7 +29,7 @@ class TestCurrent(TestsBase):
         """dowgrade a v3 notebook to v2"""
         # Open a version 3 notebook.
         with self.fopen(u'test3.ipynb', 'r') as f:
-            nb = read(f, u'json')
+            nb = read(f, as_version=3)
 
         jsons = writes(nb, version=2)
         nb2 = json.loads(jsons)
diff --git a/IPython/nbformat/tests/test_convert.py b/IPython/nbformat/tests/test_convert.py
index 19c8b35..06ca145 100644
--- a/IPython/nbformat/tests/test_convert.py
+++ b/IPython/nbformat/tests/test_convert.py
@@ -5,9 +5,9 @@
 
 from .base import TestsBase
 
-from ..convert import convert
+from ..converter import convert
 from ..reader import read, get_version
-from ..current import current_nbformat
+from .. import current_nbformat
 
 
 class TestConvert(TestsBase):
diff --git a/IPython/nbformat/tests/test_sign.py b/IPython/nbformat/tests/test_sign.py
index 5534105..286a10a 100644
--- a/IPython/nbformat/tests/test_sign.py
+++ b/IPython/nbformat/tests/test_sign.py
@@ -3,10 +3,9 @@
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
-from .. import sign
 from .base import TestsBase
 
-from ..current import read
+from IPython.nbformat import read, sign
 from IPython.core.getipython import get_ipython
 
 
@@ -18,7 +17,7 @@ class TestNotary(TestsBase):
             profile_dir=get_ipython().profile_dir
         )
         with self.fopen(u'test3.ipynb', u'r') as f:
-            self.nb = read(f, u'json')
+            self.nb = read(f, as_version=4)
     
     def test_algorithms(self):
         last_sig = ''
diff --git a/IPython/nbformat/tests/test_validator.py b/IPython/nbformat/tests/test_validator.py
index 92b04fe..a084282 100644
--- a/IPython/nbformat/tests/test_validator.py
+++ b/IPython/nbformat/tests/test_validator.py
@@ -7,7 +7,7 @@ import os
 
 from .base import TestsBase
 from jsonschema import ValidationError
-from ..current import read
+from IPython.nbformat import read
 from ..validator import isvalid, validate
 
 
@@ -16,21 +16,21 @@ class TestValidator(TestsBase):
     def test_nb2(self):
         """Test that a v2 notebook converted to current passes validation"""
         with self.fopen(u'test2.ipynb', u'r') as f:
-            nb = read(f, u'json')
+            nb = read(f, as_version=4)
         validate(nb)
         self.assertEqual(isvalid(nb), True)
 
     def test_nb3(self):
         """Test that a v3 notebook passes validation"""
         with self.fopen(u'test3.ipynb', u'r') as f:
-            nb = read(f, u'json')
+            nb = read(f, as_version=4)
         validate(nb)
         self.assertEqual(isvalid(nb), True)
 
     def test_nb4(self):
         """Test that a v4 notebook passes validation"""
         with self.fopen(u'test4.ipynb', u'r') as f:
-            nb = read(f, u'json')
+            nb = read(f, as_version=4)
         validate(nb)
         self.assertEqual(isvalid(nb), True)
 
@@ -41,7 +41,7 @@ class TestValidator(TestsBase):
         # - invalid cell type
         # - invalid output_type
         with self.fopen(u'invalid.ipynb', u'r') as f:
-            nb = read(f, u'json')
+            nb = read(f, as_version=4)
         with self.assertRaises(ValidationError):
             validate(nb)
         self.assertEqual(isvalid(nb), False)
@@ -49,7 +49,7 @@ class TestValidator(TestsBase):
     def test_future(self):
         """Test than a notebook from the future with extra keys passes validation"""
         with self.fopen(u'test4plus.ipynb', u'r') as f:
-            nb = read(f)
+            nb = read(f, as_version=4)
         with self.assertRaises(ValidationError):
             validate(nb, version=4)
         
diff --git a/IPython/nbformat/v4/convert.py b/IPython/nbformat/v4/convert.py
index a73f2e6..37e5330 100644
--- a/IPython/nbformat/v4/convert.py
+++ b/IPython/nbformat/v4/convert.py
@@ -16,7 +16,7 @@ from IPython.utils.log import get_logger
 
 def _warn_if_invalid(nb, version):
     """Log validation errors, if there are any."""
-    from IPython.nbformat.current import validate, ValidationError
+    from IPython.nbformat import validate, ValidationError
     try:
         validate(nb, version=version)
     except ValidationError as e:
diff --git a/IPython/nbformat/v4/nbbase.py b/IPython/nbformat/v4/nbbase.py
index 925992f..586f399 100644
--- a/IPython/nbformat/v4/nbbase.py
+++ b/IPython/nbformat/v4/nbbase.py
@@ -19,7 +19,7 @@ nbformat_schema = 'nbformat.v4.schema.json'
 
 def validate(node, ref=None):
     """validate a v4 node"""
-    from ..current import validate
+    from .. import validate
     return validate(node, ref=ref, version=nbformat)
 
 
diff --git a/IPython/nbformat/v4/tests/test_convert.py b/IPython/nbformat/v4/tests/test_convert.py
index 3cfe8da..4e9c0e5 100644
--- a/IPython/nbformat/v4/tests/test_convert.py
+++ b/IPython/nbformat/v4/tests/test_convert.py
@@ -2,7 +2,7 @@ import copy
 
 import nose.tools as nt
 
-from IPython.nbformat.current import validate
+from IPython.nbformat import validate
 from .. import convert
 
 from . import nbexamples
diff --git a/IPython/nbformat/validator.py b/IPython/nbformat/validator.py
index 040ce66..a4fcd86 100644
--- a/IPython/nbformat/validator.py
+++ b/IPython/nbformat/validator.py
@@ -43,7 +43,8 @@ def _relax_additional_properties(obj):
 def get_validator(version=None, version_minor=None):
     """Load the JSON schema into a Validator"""
     if version is None:
-        from .current import nbformat as version
+        from .. import current_nbformat
+        version = current_nbformat
 
     v = import_item("IPython.nbformat.v%s" % version)
     current_minor = v.nbformat_minor