AppΒΆ
App is a very small utility library. It only contains the import method. But, with the import method, you can accomplish a lot.
// examples
App::Import('Core','File');
App::Import('Model','Post');
App::import('Vendor', 'geshi');
App::import('Vendor', 'flickr/flickr');
App::import('Vendor', 'SomeName', array('file' => 'some.name.php'));
App::import('Vendor', 'WellNamed', array('file' => 'services'.DS.'well.named.php'));
You can read more about it in the book or the API documentation