diff --git a/CHANGELOG.md b/CHANGELOG.md
index d9ffc910..def4ab8c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@
     `create` so that an exception gets raised if it is appropriate to do so.
   - [#199](https://github.com/airblade/paper_trail/pull/199) - Rails 4 compatibility.
   - [#165](https://github.com/airblade/paper_trail/pull/165) - Namespaced the version class under the `PaperTrail` module.
+  - [#119](https://github.com/airblade/paper_trail/issues/119) - Support for [Sinatra](http://www.sinatrarb.com/); decoupled gem from `Rails`.
   
 
 ## 2.7.2
diff --git a/README.md b/README.md
index 55c7fc6c..91ccd11a 100644
--- a/README.md
+++ b/README.md
@@ -54,6 +54,22 @@ The Rails 2.3 code is on the [`rails2`](https://github.com/airblade/paper_trail/
 
 4. Add `has_paper_trail` to the models you want to track.
 
+### Sinatra
+
+PaperTrail provides a helper extension that acts similar to the controller mixin it provides for `Rails` applications.
+
+It will set `PaperTrail.whodunnit` to whatever is returned by a method named `user_for_paper_trail` which you can define inside your Sinatra Application. (by default it attempts to invoke a method named `current_user`)
+
+If you're using the modular [Sinatra::Base](http://www.sinatrarb.com/intro.html#Modular%20vs.%20Classic%20Style) style of application, you will need to register the extension:
+
+```ruby
+# bleh_app.rb
+require 'sinatra/base'
+
+class BlehApp < Sinatra::Base
+  register PaperTrail::Sinatra
+end
+```
 
 ## API Summary
 
diff --git a/gemfiles/3.0.gemfile b/gemfiles/3.0.gemfile
index f66bf913..17d23354 100644
--- a/gemfiles/3.0.gemfile
+++ b/gemfiles/3.0.gemfile
@@ -1,6 +1,5 @@
 source 'https://rubygems.org'
 
-gem 'railties', '~> 3.0'
 gem 'activerecord', '~> 3.0'
 
 group :development, :test do
@@ -8,6 +7,13 @@ group :development, :test do
   gem 'shoulda', '~> 3.5'
   gem 'ffaker',  '>= 1.15'
 
+  # Testing of Rails
+  gem 'railties', '~> 3.0'
+
+  # Testing of Sinatra
+  gem 'sinatra', '~> 1.0'
+  gem 'rack-test', '>= 0.6'
+
   # Use sqlite3 gem for regular Ruby
   gem 'sqlite3', '~> 1.2', :platform => :ruby
 
diff --git a/lib/paper_trail.rb b/lib/paper_trail.rb
index 3d5f9fe9..f58da83f 100644
--- a/lib/paper_trail.rb
+++ b/lib/paper_trail.rb
@@ -1,10 +1,10 @@
 require 'paper_trail/config'
-require 'paper_trail/controller'
 require 'paper_trail/has_paper_trail'
 require 'paper_trail/cleaner'
 
-require 'paper_trail/serializers/yaml'
-require 'paper_trail/serializers/json'
+# Require all frameworks and serializers
+Dir[File.join(File.dirname(__FILE__), 'paper_trail', 'frameworks', '*.rb')].each { |file| require file }
+Dir[File.join(File.dirname(__FILE__), 'paper_trail', 'serializers', '*.rb')].each { |file| require file }
 
 # PaperTrail's module methods can be called in both models and controllers.
 module PaperTrail
@@ -88,9 +88,7 @@ module PaperTrail
   # Thread-safe hash to hold PaperTrail's data.
   # Initializing with needed default values.
   def self.paper_trail_store
-    Thread.current[:paper_trail] ||= {
-      :request_enabled_for_controller => true
-    }
+    Thread.current[:paper_trail] ||= { :request_enabled_for_controller => true }
   end
 
   # Returns PaperTrail's configuration object.
@@ -110,6 +108,8 @@ ActiveSupport.on_load(:active_record) do
   include PaperTrail::Model
 end
 
-ActiveSupport.on_load(:action_controller) do
-  include PaperTrail::Controller
+if defined?(ActionController)
+  ActiveSupport.on_load(:action_controller) do
+    include PaperTrail::Rails::Controller
+  end
 end
diff --git a/lib/paper_trail/controller.rb b/lib/paper_trail/controller.rb
deleted file mode 100644
index 6bbbe70a..00000000
--- a/lib/paper_trail/controller.rb
+++ /dev/null
@@ -1,75 +0,0 @@
-module PaperTrail
-  module Controller
-
-    def self.included(base)
-      base.before_filter :set_paper_trail_enabled_for_controller
-      base.before_filter :set_paper_trail_whodunnit, :set_paper_trail_controller_info
-    end
-
-    protected
-
-    # Returns the user who is responsible for any changes that occur.
-    # By default this calls `current_user` and returns the result.
-    #
-    # Override this method in your controller to call a different
-    # method, e.g. `current_person`, or anything you like.
-    def user_for_paper_trail
-      current_user if defined?(current_user)
-    end
-
-    # Returns any information about the controller or request that you
-    # want PaperTrail to store alongside any changes that occur.  By
-    # default this returns an empty hash.
-    #
-    # Override this method in your controller to return a hash of any
-    # information you need.  The hash's keys must correspond to columns
-    # in your `versions` table, so don't forget to add any new columns
-    # you need.
-    #
-    # For example:
-    #
-    #     {:ip => request.remote_ip, :user_agent => request.user_agent}
-    #
-    # The columns `ip` and `user_agent` must exist in your `versions` # table.
-    #
-    # Use the `:meta` option to `PaperTrail::Model::ClassMethods.has_paper_trail`
-    # to store any extra model-level data you need.
-    def info_for_paper_trail
-      {}
-    end
-
-    # Returns `true` (default) or `false` depending on whether PaperTrail should
-    # be active for the current request.
-    #
-    # Override this method in your controller to specify when PaperTrail should
-    # be off.
-    def paper_trail_enabled_for_controller
-      true
-    end
-
-    private
-
-    # Tells PaperTrail whether versions should be saved in the current request.
-    def set_paper_trail_enabled_for_controller
-      ::PaperTrail.enabled_for_controller = paper_trail_enabled_for_controller
-    end
-
-    # Tells PaperTrail who is responsible for any changes that occur.
-    def set_paper_trail_whodunnit
-      ::PaperTrail.whodunnit = user_for_paper_trail if paper_trail_enabled_for_controller
-    end
-
-    # DEPRECATED: please use `set_paper_trail_whodunnit` instead.
-    def set_whodunnit
-      logger.warn '[PaperTrail]: the `set_whodunnit` controller method has been deprecated.  Please rename to `set_paper_trail_whodunnit`.'
-      set_paper_trail_whodunnit
-    end
-
-    # Tells PaperTrail any information from the controller you want
-    # to store alongside any changes that occur.
-    def set_paper_trail_controller_info
-      ::PaperTrail.controller_info = info_for_paper_trail if paper_trail_enabled_for_controller
-    end
-
-  end
-end
diff --git a/lib/paper_trail/frameworks/rails.rb b/lib/paper_trail/frameworks/rails.rb
new file mode 100644
index 00000000..cbef5d9f
--- /dev/null
+++ b/lib/paper_trail/frameworks/rails.rb
@@ -0,0 +1,79 @@
+module PaperTrail
+  module Rails
+    module Controller
+
+      def self.included(base)
+        if defined?(ActionController) && base == ActionController::Base
+          base.before_filter :set_paper_trail_enabled_for_controller
+          base.before_filter :set_paper_trail_whodunnit, :set_paper_trail_controller_info
+        end
+      end
+
+      protected
+
+      # Returns the user who is responsible for any changes that occur.
+      # By default this calls `current_user` and returns the result.
+      #
+      # Override this method in your controller to call a different
+      # method, e.g. `current_person`, or anything you like.
+      def user_for_paper_trail
+        current_user if defined?(current_user)
+      end
+
+      # Returns any information about the controller or request that you
+      # want PaperTrail to store alongside any changes that occur.  By
+      # default this returns an empty hash.
+      #
+      # Override this method in your controller to return a hash of any
+      # information you need.  The hash's keys must correspond to columns
+      # in your `versions` table, so don't forget to add any new columns
+      # you need.
+      #
+      # For example:
+      #
+      #     {:ip => request.remote_ip, :user_agent => request.user_agent}
+      #
+      # The columns `ip` and `user_agent` must exist in your `versions` # table.
+      #
+      # Use the `:meta` option to `PaperTrail::Model::ClassMethods.has_paper_trail`
+      # to store any extra model-level data you need.
+      def info_for_paper_trail
+        {}
+      end
+
+      # Returns `true` (default) or `false` depending on whether PaperTrail should
+      # be active for the current request.
+      #
+      # Override this method in your controller to specify when PaperTrail should
+      # be off.
+      def paper_trail_enabled_for_controller
+        true
+      end
+
+      private
+
+      # Tells PaperTrail whether versions should be saved in the current request.
+      def set_paper_trail_enabled_for_controller
+        ::PaperTrail.enabled_for_controller = paper_trail_enabled_for_controller
+      end
+
+      # Tells PaperTrail who is responsible for any changes that occur.
+      def set_paper_trail_whodunnit
+        ::PaperTrail.whodunnit = user_for_paper_trail if paper_trail_enabled_for_controller
+      end
+
+      # DEPRECATED: please use `set_paper_trail_whodunnit` instead.
+      def set_whodunnit
+        logger.warn '[PaperTrail]: the `set_whodunnit` controller method has been deprecated.  Please rename to `set_paper_trail_whodunnit`.'
+        set_paper_trail_whodunnit
+      end
+
+      # Tells PaperTrail any information from the controller you want
+      # to store alongside any changes that occur.
+      def set_paper_trail_controller_info
+        ::PaperTrail.controller_info = info_for_paper_trail if paper_trail_enabled_for_controller
+      end
+
+    end
+  end
+end
diff --git a/lib/paper_trail/frameworks/sinatra.rb b/lib/paper_trail/frameworks/sinatra.rb
new file mode 100644
index 00000000..eec7d4f3
--- /dev/null
+++ b/lib/paper_trail/frameworks/sinatra.rb
@@ -0,0 +1,35 @@
+module PaperTrail
+  module Sinatra
+
+    # Register this module inside your Sinatra application to gain access to controller-level methods used by PaperTrail
+    def self.registered(app)
+      app.helpers PaperTrail::Sinatra
+      app.before { set_paper_trail_whodunnit }
+    end
+
+    protected
+
+    # Returns the user who is responsible for any changes that occur.
+    # By default this calls `current_user` and returns the result.
+    #
+    # Override this method in your controller to call a different
+    # method, e.g. `current_person`, or anything you like.
+    def user_for_paper_trail
+      current_user if defined?(current_user)
+    end
+
+    private
+
+    # Tells PaperTrail who is responsible for any changes that occur.
+    def set_paper_trail_whodunnit
+      ::PaperTrail.whodunnit = user_for_paper_trail if ::PaperTrail.enabled?
+    end
+
+  end
+end
+
+if defined?(Sinatra)
+  module Sinatra
+    register PaperTrail::Sinatra
+  end
+end
diff --git a/paper_trail.gemspec b/paper_trail.gemspec
index d1194140..1470eb41 100644
--- a/paper_trail.gemspec
+++ b/paper_trail.gemspec
@@ -15,12 +15,14 @@ Gem::Specification.new do |s|
   s.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
   s.require_paths = ['lib']
 
-  s.add_dependency 'railties', ['>= 3.0', '< 5.0']
   s.add_dependency 'activerecord', ['>= 3.0', '< 5.0']
 
   s.add_development_dependency 'rake'
   s.add_development_dependency 'shoulda', '~> 3.5'
   s.add_development_dependency 'ffaker',  '>= 1.15'
+  s.add_development_dependency 'railties', ['>= 3.0', '< 5.0']
+  s.add_development_dependency 'sinatra', '~> 1.0'
+  s.add_development_dependency 'rack-test', '>= 0.6'
 
   # JRuby support for the test ENV
   unless defined?(JRUBY_VERSION)
diff --git a/test/functional/sinatra_test.rb b/test/functional/sinatra_test.rb
new file mode 100644
index 00000000..8c698582
--- /dev/null
+++ b/test/functional/sinatra_test.rb
@@ -0,0 +1,88 @@
+require 'test_helper'
+require 'sinatra/base'
+
+# --- Tests for modular `Sinatra::Base` style ----
+class BaseApp < Sinatra::Base
+  ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: File.expand_path('../../dummy/db/test.sqlite3', __FILE__))
+  register PaperTrail::Sinatra
+
+  get '/test' do
+    w = Widget.create!(name: 'foo')
+    'Hello'
+  end
+
+  def current_user
+    'foobar'
+  end
+end
+
+class PaperTrailModularSinatraTest < ActiveSupport::TestCase
+  include Rack::Test::Methods
+
+  test 'baseline' do
+    assert_nil Widget.first
+    assert_nil Widget.create.versions.first.whodunnit
+  end
+
+  context "`PaperTrail::Sinatra` in a `Sinatra::Base` application" do
+
+    def app
+      @app ||= BaseApp
+    end
+  
+    should "sets the `user_for_paper_trail` from the `current_user` method" do
+      get '/test'
+      assert_equal 'Hello', last_response.body
+      widget = Widget.first
+      assert_not_nil widget
+      assert_equal 1, widget.versions.size
+      assert_equal 'foobar', widget.versions.first.whodunnit
+    end
+
+  end
+end
+
+# --- Tests for non-modular `Sinatra::Application` style ----
+class Sinatra::Application
+  ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: File.expand_path('../../dummy/db/test.sqlite3', __FILE__))
+
+  get '/test' do
+    w = Widget.create!(name: 'foo')
+    'Hello'
+  end
+
+  def current_user
+    'foobar'
+  end
+end
+
+class PaperTrailSinatraTest < ActiveSupport::TestCase
+  include Rack::Test::Methods
+
+  def app
+    @app ||= Sinatra::Application
+  end
+
+  test 'baseline' do
+    assert_nil Widget.first
+    assert_nil Widget.create.versions.first.whodunnit
+  end
+
+  context "`PaperTrail::Sinatra` in a `Sinatra::Application` application" do
+
+    def app
+      @app ||= BaseApp
+    end
+
+    should "sets the `user_for_paper_trail` from the `current_user` method" do
+      get '/test'
+      assert_equal 'Hello', last_response.body
+      widget = Widget.first
+      assert_not_nil widget
+      assert_equal 1, widget.versions.size
+      assert_equal 'foobar', widget.versions.first.whodunnit
+    end
+
+  end
+end
+