diff --git a/googlemaps/__init__.py b/googlemaps/__init__.py
index 9381dc6c..0662968b 100644
--- a/googlemaps/__init__.py
+++ b/googlemaps/__init__.py
@@ -1,7 +1,7 @@
-from context import Context
-from directions import directions
-from geocoding import geocode
-from geocoding import reverse_geocode
+from googlemaps.common import Context
+from googlemaps.directions import directions
+from googlemaps.geocoding import geocode
+from googlemaps.geocoding import reverse_geocode
 
 # Allow sphinx to pick up these symbols for the documentation.
 __all__ = ['Context', 'geocode', 'reverse_geocode', 'directions']
diff --git a/googlemaps/common.py b/googlemaps/common.py
index a0eb4212..345646bd 100644
--- a/googlemaps/common.py
+++ b/googlemaps/common.py
@@ -1,5 +1,38 @@
+"""
+Common functionality for modules in the googlemaps package, such as performing
+HTTP requests.
+"""
+
 import requests
 
+
+class Context(object):
+    """Holds state between requests, such as credentials (API key), timeout
+    settings"""
+
+    def __init__(self, key=None, client_id=None, client_secret=None,
+                 timeout=None):
+        """
+        :param key: Maps API key. Required, unless "client_id" and
+            "client_secret" are set.
+        :type key: basestring
+
+        :param timeout: Timeout for requests, in seconds.
+        :type timeout: int
+
+        :param client_id: (for Maps API for Work customers) Your client ID.
+        :type client_id: basestring
+
+        :param client_secret: (for Maps API for Work customers) Your client
+            secret (base64 encoded).
+        :type client_secret: basestring
+        """
+        # TODO(lukem): simple key validation.
+        self.key = key
+        self.timeout = timeout
+        self.client_id = client_id
+        self.client_secret = client_secret
+
 def _get(ctx, url, params):
     """Performs HTTP GET request with credentials, returning the body as JSON.
 
@@ -13,19 +46,20 @@ def _get(ctx, url, params):
 
     # TODO(mdr-eng): implement rate limiting, retries, etc.
     # TODO(mdr-eng): implement enterprise key signing
+    # TODO(mdr-eng): enforce use of API keys/credentials
     # TODO(mdr-eng): add jitter (might not be necessary since most uses will be
     #       single threaded)
     params["key"] = ctx.key
     resp = requests.get(
-            "https://maps.googleapis.com" + url,
-            verify=True, # NOTE(cbro): verify SSL certs.
-            params=params)
+        "https://maps.googleapis.com" + url,
+        verify=True, # NOTE(cbro): verify SSL certs.
+        params=params)
 
     # TODO(mdr-eng): better error handling
     if resp.status_code != 200:
         raise Exception(
-                "Unexpected response: [%d] %s" %
-                (resp.status_code, resp.text))
+            "Unexpected response: [%d] %s" %
+            (resp.status_code, resp.text))
 
     body = resp.json()
 
diff --git a/googlemaps/context.py b/googlemaps/context.py
deleted file mode 100644
index 05cb9487..00000000
--- a/googlemaps/context.py
+++ /dev/null
@@ -1,16 +0,0 @@
-import requests
-
-
-class Context(object):
-
-    def __init__(self, key, timeout=None):
-        """
-        :param key: Maps API key. Required, unless "client_id" and "client_secret" are set.
-        :type key: basestring
-
-        :param timeout: Timeout for requests, in seconds.
-        :type timeout: int
-        """
-        # TODO(lukem): simple key validation.
-        self.key = key
-        self.timeout = timeout
diff --git a/googlemaps/convert.py b/googlemaps/convert.py
index 686b8f6b..5c4629a8 100644
--- a/googlemaps/convert.py
+++ b/googlemaps/convert.py
@@ -14,7 +14,7 @@
 import time as _time
 
 
-def latlng(ll):
+def latlng(arg):
     """Converts a lat/lon pair to a comma-separated string.
 
     Accepts various representations:
@@ -32,59 +32,71 @@ def latlng(ll):
     convert.latlng(sydney)
     # '-33.8674869,151.2069902'
 
-    :param ll: The lat/lon pair.
-    :type ll: basestring or dict or list
+    :param arg: The lat/lon pair.
+    :type arg: basestring or dict or list
     """
-    if isinstance(ll, basestring):
-        return ll
+    if isinstance(arg, basestring):
+        return arg
 
-    if isinstance(ll, dict):
-        if "lat" in ll and "lng" in ll:
-            return "%f,%f" % (ll["lat"], ll["lng"])
+    if isinstance(arg, dict):
+        if "lat" in arg and "lng" in arg:
+            return "%f,%f" % (arg["lat"], arg["lng"])
 
     # List or tuple.
-    if _is_list(ll):
-        return "%f,%f" % (ll[0], ll[1])
+    if _is_list(arg):
+        return "%f,%f" % (arg[0], arg[1])
 
     raise TypeError(
-            "Expected a string or lat/lng dict, "
-            "but got %s" % type(o).__name__)
+        "Expected a string or lat/lng dict, "
+        "but got %s" % type(arg).__name__)
 
 
-def join_list(sep, l):
-    return sep.join(as_list(l))
+def join_list(sep, arg):
+    """If arg is list-like, then joins it with sep.
+    :param sep: Separator string.
+    :type sep: basestring
+    :param arg: Value to coerce into a list.
+    :type arg: basestring or list
+    :rtype: basestring
+    """
+    return sep.join(as_list(arg))
 
 
-def as_list(l):
-    if _is_list(l):
-        return l
-    return [l]
+def as_list(arg):
+    """Coerces arg into a list. If arg is already list-like, returns arg.
+    Otherwise, returns a one-element list containing arg.
+    :rtype: list
+    """
+    if _is_list(arg):
+        return arg
+    return [arg]
 
 
 def _is_list(arg):
+    """Checks if arg is list-like. This excludes strings."""
     return (not _has_method(arg, "strip")
-        and _has_method(arg, "__getitem__")
-        or _has_method(arg, "__iter__"))
+            and _has_method(arg, "__getitem__")
+            or _has_method(arg, "__iter__"))
 
 
-def time(t):
+def time(arg):
     """Converts the value into a unix time (seconds since unix epoch).
 
     For example:
         convert.time(datetime.now())
         # '1409810596'
 
-    :param t: The time.
-    :type t: datetime.datetime or int
+    :param arg: The time.
+    :type arg: datetime.datetime or int
     """
     # handle datetime instances.
-    if _has_method(t, "timetuple"):
-        t = _time.mktime(t.timetuple())
+    if _has_method(arg, "timetuple"):
+        arg = _time.mktime(arg.timetuple())
 
-    if isinstance(t, float):
-        t = int(t)
+    if isinstance(arg, float):
+        arg = int(arg)
 
-    return str(t)
+    return str(arg)
 
 
 def _has_method(arg, method):
@@ -98,7 +110,7 @@ def _has_method(arg, method):
     return hasattr(arg, method) and callable(getattr(arg, method))
 
 
-def components(c):
+def components(arg):
     """Converts a dict of components to the format expected by the Google Maps
     server.
 
@@ -107,31 +119,59 @@ def components(c):
     convert.components(c)
     # 'country:US|postal_code:94043'
 
-    :param c: The component filter.
-    :type c: dict or basestring
+    :param arg: The component filter.
+    :type arg: dict or basestring
     :rtype basestring:
     """
-    if isinstance(c, basestring):
-        return c
+    if isinstance(arg, basestring):
+        return arg
 
-    if isinstance(c, dict):
-        c = ["%s:%s" % (k, c[k]) for k in c]
-        return "|".join(c)
+    if isinstance(arg, dict):
+        arg = ["%s:%s" % (k, arg[k]) for k in arg]
+        return "|".join(arg)
 
     raise TypeError(
-            "Expected a string or dict for components, "
-            "but got %s" % type(c).__name__)
+        "Expected a string or dict for components, "
+        "but got %s" % type(arg).__name__)
+
 
+def bounds(arg):
+    """Converts a lat/lon bounds to a comma- and pipe-separated string.
+
+    Accepts two representations:
+    1) string: pipe-separated pair of comma-separated lat/lon pairs.
+    2) dict with two entries - "southwest" and "northeast". See convert.latlng
+    for information on how these can be represented.
+
+    For example:
+
+    sydney_bounds = {
+        "northeast" : {
+            "lat" : -33.4245981,
+            "lng" : 151.3426361
+        },
+        "southwest" : {
+            "lat" : -34.1692489,
+            "lng" : 150.502229
+        }
+    }
+
+    convert.bounds(sydney_bounds)
+    # '-34.169249,150.502229|-33.424598,151.342636'
+
+    :param arg: The bounds.
+    :type arg: basestring or dict
+    """
 
-def bounds(b):
-    if isinstance(b, basestring):
-        return b
+    if isinstance(arg, basestring):
+        return arg
 
-    if isinstance(b, dict):
-        if "southwest" in b and "northeast" in b:
-            return "%s|%s" % (latlng(b["southwest"]), latlng(b["northeast"]))
+    if isinstance(arg, dict):
+        if "southwest" in arg and "northeast" in arg:
+            return "%s|%s" % (latlng(arg["southwest"]),
+                              latlng(arg["northeast"]))
 
     raise TypeError(
-            "Expected a string or bounds (southwest/northeast) dict, "
-            "but got %s" % type(b).__name__)
+        "Expected a string or bounds (southwest/northeast) dict, "
+        "but got %s" % type(arg).__name__)
 
diff --git a/googlemaps/directions.py b/googlemaps/directions.py
index 68d2d199..d938d934 100644
--- a/googlemaps/directions.py
+++ b/googlemaps/directions.py
@@ -1,11 +1,13 @@
-import common
-import convert
+"""Performs requests to the Google Maps Directions API."""
+
+from googlemaps import common
+from googlemaps import convert
 
 
 def directions(ctx, origin, destination,
-        mode=None, waypoints=None, alternatives=False, avoid=None,
-        language=None, units=None, region=None, departure_time=None,
-        arrival_time=None):
+               mode=None, waypoints=None, alternatives=False, avoid=None,
+               language=None, units=None, region=None, departure_time=None,
+               arrival_time=None):
     """Get directions between an origin point and a destination point.
 
     :param ctx: Shared googlemaps.Context
@@ -48,7 +50,8 @@ def directions(ctx, origin, destination,
     :param departure_time: Specifies the desired time of departure.
     :type departure_time: int or datetime.datetime
 
-    :param arrival_time: Specifies the desired time of arrival for transit directions.
+    :param arrival_time: Specifies the desired time of arrival for transit
+        directions.
     :type arrival_time: int or datetime.datetime
 
     :rtype: list of routes
diff --git a/googlemaps/geocoding.py b/googlemaps/geocoding.py
index 1a17d9d5..4cf4e17c 100644
--- a/googlemaps/geocoding.py
+++ b/googlemaps/geocoding.py
@@ -1,9 +1,11 @@
-import common
-import convert
+"""Performs requests to the Google Maps Geocoding API."""
+from googlemaps import common
+from googlemaps import convert
 
 
 # TODO(mdr-eng): test unicode parameters (e.g. in addresses).
-def geocode(ctx, address=None, components=None, bounds=None, region=None, language=None):
+def geocode(ctx, address=None, components=None, bounds=None, region=None,
+            language=None):
     """
     Geocoding is the process of converting addresses
     (like "1600 Amphitheatre Parkway, Mountain View, CA") into geographic
@@ -31,7 +33,8 @@ def geocode(ctx, address=None, components=None, bounds=None, region=None, langua
     return common._get(ctx, "/maps/api/geocode/json", params)["results"]
 
 
-def reverse_geocode(ctx, latlng, result_type=None, location_type=None, language=None):
+def reverse_geocode(ctx, latlng, result_type=None, location_type=None,
+                    language=None):
     """
     Reverse geocoding is the process of converting geographic coordinates into a
     human-readable address.