diff --git a/.gitignore b/.gitignore
index 06e83d4..3e5e35b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,5 @@ components
 build
 node_modules
 /lib
+/domains
+/setimmediate
diff --git a/Readme.md b/Readme.md
index 04f9f92..92beeeb 100644
--- a/Readme.md
+++ b/Readme.md
@@ -43,7 +43,7 @@ Note that the [es5-shim](https://github.com/es-shims/es5-shim) must be loaded be
 
 ## Usage
 
-The example below shows how you can load the promise library (in a way that works on both client and server).  It then demonstrates creating a promise from scratch.  You simply call `new Promise(fn)`.  There is a complete specification for what is returned by this method in [Promises/A+](http://promises-aplus.github.com/promises-spec/).
+The example below shows how you can load the promise library (in a way that works on both client and server using node or browserify).  It then demonstrates creating a promise from scratch.  You simply call `new Promise(fn)`.  There is a complete specification for what is returned by this method in [Promises/A+](http://promises-aplus.github.com/promises-spec/).
 
 ```javascript
 var Promise = require('promise');
@@ -56,6 +56,26 @@ var promise = new Promise(function (resolve, reject) {
 });
 ```
 
+If you need [domains](https://iojs.org/api/domain.html) support, you should instead use:
+
+```js
+var Promise = require('promise/domains');
+```
+
+If you are in an environment that implements `setImmediate` and don't want the optimisations provided by asap, you can use:
+
+```js
+var Promise = require('promise/setimmediate');
+```
+
+If you only want part of the features, e.g. just a pure ES6 polyfill:
+
+```js
+var Promise = require('promise/lib/es6-extensions');
+// or require('promise/domains/es6-extensions');
+// or require('promise/setimmediate/es6-extensions');
+```
+
 ## API
 
 Before all examples, you will need:
diff --git a/build.js b/build.js
index 7266c63..0f45323 100644
--- a/build.js
+++ b/build.js
@@ -48,3 +48,22 @@ fs.readdirSync(__dirname + '/src').forEach(function (filename) {
   var out = fixup(src);
   fs.writeFileSync(__dirname + '/lib/' + filename, out);
 });
+
+rimraf.sync(__dirname + '/domains/');
+fs.mkdirSync(__dirname + '/domains/');
+fs.readdirSync(__dirname + '/src').forEach(function (filename) {
+  var src = fs.readFileSync(__dirname + '/src/' + filename, 'utf8');
+  var out = fixup(src);
+  out = out.replace(/require\(\'asap\/raw\'\)/g, "require('asap')");
+  fs.writeFileSync(__dirname + '/domains/' + filename, out);
+});
+
+rimraf.sync(__dirname + '/setimmediate/');
+fs.mkdirSync(__dirname + '/setimmediate/');
+fs.readdirSync(__dirname + '/src').forEach(function (filename) {
+  var src = fs.readFileSync(__dirname + '/src/' + filename, 'utf8');
+  var out = fixup(src);
+  out = out.replace(/var asap \= require\(\'([a-z\/]+)\'\)/g, '');
+  out = out.replace(/asap/g, "setImmediate");
+  fs.writeFileSync(__dirname + '/setimmediate/' + filename, out);
+});
diff --git a/index.js b/index.js
index 193c654..1c38e46 100644
--- a/index.js
+++ b/index.js
@@ -1,7 +1,3 @@
 'use strict';
 
-module.exports = require('./lib/core.js')
-require('./lib/done.js')
-require('./lib/finally.js')
-require('./lib/es6-extensions.js')
-require('./lib/node-extensions.js')
+module.exports = require('./lib')
diff --git a/package.json b/package.json
index ba0b800..96db9a7 100644
--- a/package.json
+++ b/package.json
@@ -4,6 +4,7 @@
   "description": "Bare bones Promises/A+ implementation",
   "main": "index.js",
   "scripts": {
+    "prepublish": "node build",
     "pretest": "node build",
     "pretest-resolve": "node build",
     "pretest-extensions": "node build",
diff --git a/src/done.js b/src/done.js
index 2da6208..4b248ed 100644
--- a/src/done.js
+++ b/src/done.js
@@ -1,14 +1,13 @@
 'use strict';
 
 var Promise = require('./core.js')
-var asap = require('asap')
 
 module.exports = Promise
 Promise.prototype.done = function (onFulfilled, onRejected) {
   var self = arguments.length ? this.then.apply(this, arguments) : this
   self.then(null, function (err) {
-    asap(function () {
+    setTimeout(function () {
       throw err
-    })
+    }, 0)
   })
 }
\ No newline at end of file
diff --git a/src/es6-extensions.js b/src/es6-extensions.js
index beb7215..8d7159b 100644
--- a/src/es6-extensions.js
+++ b/src/es6-extensions.js
@@ -3,7 +3,7 @@
 //This file contains the ES6 extensions to the core Promises/A+ API
 
 var Promise = require('./core.js')
-var asap = require('asap')
+var asap = require('asap/raw')
 
 module.exports = Promise
 
diff --git a/src/index.js b/src/index.js
new file mode 100644
index 0000000..1af7bad
--- /dev/null
+++ b/src/index.js
@@ -0,0 +1,7 @@
+'use strict';
+
+module.exports = require('./core.js')
+require('./done.js')
+require('./finally.js')
+require('./es6-extensions.js')
+require('./node-extensions.js')