WP.Autoload (formerly PHP Autoload Manager) was created to allow me to easily extend the power of WordPress by using PHP’s autoload function to quic
Many developers writing object-oriented applications create one PHP source file per class definition. One of the biggest annoyances is having to write a long list of needed includes at the beginning of each script (one for each class). In PHP 5, this is no longer necessary. You may define an __autoload() function which is automatically called in case you are trying to use a class/interface which hasn’t been defined yet. By calling this function the scripting engine is given a last chance to load the class before PHP fails with an error http://php.net/manual/en/language.oop5.autoload.php.