diff --git a/README.md b/README.md
index 529e581..35bf1ce 100644
--- a/README.md
+++ b/README.md
@@ -67,8 +67,20 @@ Check out the README within the sass directory for more information.
 
 ## Configuration
 
-Gesso includes several theme-specific settings for managing classes output by
-Drupal, which you can change at admin/appearance/settings/gesso.
+Gesso includes several theme-specific settings for managing classes output by Drupal, which you can change at admin/appearance/settings/gesso.
+
+#### Front end tool dependencies
+__[Bundler](http://bundler.io)__ is used to manage the following dependencies and minimum required Ruby Gem versions. (Similar to [Bower](http://bower.io/), but for Ruby Gems.)
+- __[Breakpoint](http://breakpoint-sass.com):__ Easy to write media queries.
+- __[Compass](http://compass-style.org):__ Open-source Sass framework.
+- __[Sass](http://sass-lang.com):__ CSS on steroids. Adds nested rules, variables, mixins, selector inheritance, and more.
+- __[Sass Globbing](https://github.com/chriseppstein/sass-globbing):__ Adds glob-based imports to Sass.
+- __[Singularity](http://singularity.gs):__ Grid-based layout system.
+
+#### Three main non-Drupal configuration files:
+- __config.rb:__ Ruby configuration file used for Compass compilation of Sass files. _Compass settings in Gruntfile.js will override settings in config.rb._
+- __Gemfile:__ Used by Bundler. Running `bundle install` will install the correct versions of all required dependencies.
+- __Gemfile.lock:__ Generated by Bundler after running `bundle install`. Lists the exact versions installed, according to the minimum requirements set in the Gemfile.
 
 
 ## Maintainers