diff --git a/README.md b/README.md
index 82b36df..17f312e 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,13 @@ is to
 - Convert keys of parameters from one name to another name for model initialization.
 - Lock mandatory and optional columns used in a presenter.
 
+Advanced features will include
+
+- Data Conversion. Pass a callback to convert data to a certain format
+- Type Coercion. Ensure the result is a certain type. Implicit data conversion.
+- Nested Presentation. If some attributes are from associations, delegate them to presenters of associations.
+- GraphQL Support. Being the glue of GraphQL type definitions and legacy models
+
 From perspective of a serializer, a Feint preseter acts as the model it presents except for different
 attribute names. You can replace a model instance with its Feint presenter and it will work seamelessly.
 
@@ -30,11 +37,32 @@ Or install it yourself as:
 
 ## Usage
 
+Consider we have a model `User`.
+
+```ruby
+class User < ActiveRecord::Base
+  connection.create_table table_name do |f|
+    f.string  :name
+    f.string  :email
+    f.string  :country
+    f.integer :age
+    f.integer :level
+  end
+end
+```
+
+This presenter will take its attributes `name` and `age`
+
 ```ruby
 class UserPresenter < Feint::Presenter
+  attributes :name, :age
+  attribute :email, type: String
+  transform country: :nation, level: :rank
 end
 ```
 
+This presenter could be passed to the serializer
+
 ```ruby
 class UsersController < ApplicationController
   def show
@@ -44,6 +72,18 @@ class UsersController < ApplicationController
 end
 ```
 
+And render expected result
+
+```json
+{
+  "name":   "NAME",
+  "age":    "AGE",
+  "email":  "EMAIL",
+  "nation": "COUNTRY",
+  "rank":   "LEVEL",
+}
+```
+
 ## Development
 
 After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake spec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.
@@ -58,4 +98,3 @@ Bug reports and pull requests are welcome on GitHub at https://github.com/shelli
 ## License
 
 The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).
-
diff --git a/lib/feint.rb b/lib/feint.rb
index 07e2e4b..01849a0 100644
--- a/lib/feint.rb
+++ b/lib/feint.rb
@@ -2,4 +2,5 @@
 
 module Feint
   autoload :Presenter, "feint/presenter"
+  autoload :Serialization, "feint/serialization"
 end
diff --git a/lib/feint/presenter.rb b/lib/feint/presenter.rb
index fe1fd8b..12b18af 100644
--- a/lib/feint/presenter.rb
+++ b/lib/feint/presenter.rb
@@ -5,7 +5,7 @@ def initialize(model) # :nodoc:
     end
 
     class << self
-      # Takes a list of columns
+      # @param columns [Symbol] list
       def attributes(*columns)
         columns.each do |column|
           define_method column do
@@ -14,8 +14,7 @@ def attributes(*columns)
         end
       end
 
-      # Take a list of mappiings
-      # { old_column_name => new_column_name }
+      # @param mappings [Hash] keys for old names and values for new names
       def transform(mappings)
         mappings.each do |old, new|
           define_method new do
@@ -23,6 +22,25 @@ def transform(mappings)
           end
         end
       end
+
+      # @param name [Symbol]
+      # @param options [Hash]
+      # options[:key] is used as field name
+      # options[:type] is used to check type
+      def attribute(name, options = {})
+        type = options[:type] || Object
+        key  = options[:key] || name
+
+        define_method key do
+          value = @model.send(name)
+
+          if value.is_a?(type)
+            return value
+          else
+            raise TypeError, "#{name} should be #{type} and is #{value.class}"
+          end
+        end
+      end
     end
   end
 end
diff --git a/lib/feint/serialization.rb b/lib/feint/serialization.rb
new file mode 100644
index 0000000..5f41de0
--- /dev/null
+++ b/lib/feint/serialization.rb
@@ -0,0 +1,9 @@
+module Feint
+  module Serialization
+    def as_json(options = nil)
+    end
+
+    def serializable_hash(options = nil)
+    end
+  end
+end
diff --git a/spec/presenter_spec.rb b/spec/presenter_spec.rb
index fc6f07f..98f2be9 100644
--- a/spec/presenter_spec.rb
+++ b/spec/presenter_spec.rb
@@ -5,6 +5,7 @@ class User < ActiveRecord::Base
   establish_connection(adapter: "sqlite3", database: "feint.db")
   connection.create_table table_name, force: true do |t|
     t.string  :name
+    t.string  :email
     t.integer :age
   end
 end
@@ -17,6 +18,12 @@ class UserTransformer < Feint::Presenter
   transform name: :handle, age: :year
 end
 
+class UserConstraintPresenter < Feint::Presenter
+  attribute :name, key: :handle
+  attribute :email
+  attribute :age, type: String
+end
+
 describe Feint::Presenter do
   let(:user) { User.create(name: "shelling", age: 30) }
 
@@ -31,4 +38,21 @@ class UserTransformer < Feint::Presenter
     expect(user_transformer.handle).to eq(user.name)
     expect(user_transformer.year).to   eq(user.age)
   end
+
+  it "can declare single field" do
+    user_constraint_presenter = UserConstraintPresenter.new(user)
+    expect(user_constraint_presenter.handle).to eq(user.name)
+  end
+
+  it "can declare single field and guess field name" do
+    user_constraint_presenter = UserConstraintPresenter.new(user)
+    expect(user_constraint_presenter.email).to eq(user.email)
+  end
+
+  it "can declare single field and check its type" do
+    user_constraint_presenter = UserConstraintPresenter.new(user)
+    expect {
+      user_constraint_presenter.age
+    }.to raise_error(TypeError, "age should be String and is Fixnum")
+  end
 end
diff --git a/spec/serialization_spec.rb b/spec/serialization_spec.rb
new file mode 100644
index 0000000..ac27c43
--- /dev/null
+++ b/spec/serialization_spec.rb
@@ -0,0 +1,4 @@
+require "spec_helper"
+
+describe Feint::Serialization do
+end