diff --git a/README.rst b/README.rst
index 0e22799..f69da47 100644
--- a/README.rst
+++ b/README.rst
@@ -53,9 +53,22 @@ dictionaries with the requested data:
 - get_us_states_by_names()
 - get_cities_by_name(name)
 
+
+Mappers
+-------
+
+The mappers module provides function(s) to map data properties. Currently you can create a mapper that maps country properties, e. g. the `name` property to the `iso3`property, to do so you'd write the following code:
+
+    from geonamescache.mappers import country
+    mapper = country(from_key='name', to_key='iso3')
+
+    iso3 = mapper('Spain') # iso3 is assigned ESP
+
+
 TODOs
 -----
 
+- create sphinx docs
 - analyze performance of get_cities_by_name
 - call get_dataset_by_key with name of dataset, so there is no need for \*_by_names methods
 
diff --git a/geonamescache/mappers.py b/geonamescache/mappers.py
new file mode 100644
index 0000000..b5dfe9f
--- /dev/null
+++ b/geonamescache/mappers.py
@@ -0,0 +1,17 @@
+# -*- coding: utf-8 -*-
+from geonamescache import GeonamesCache
+from . import mappings
+
+
+def country(from_key='name', to_key='iso'):
+    gc = GeonamesCache()
+    dataset = gc.get_dataset_by_key(gc.get_countries(), from_key)
+
+    def mapper(key):
+        if 'name' == from_key and key in mappings.country_names:
+            key = mappings.country_names[key]
+        item = dataset.get(key)
+        if item:
+            return item[to_key]
+
+    return mapper
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