Derick Rethans
Derick Rethans is a PHP internals expert and author of Xdebug. He works as an independent contractor and consultant on PHP extensions, the PHP language, and related projects.
He works for the PHP Foundation to improve PHP, and continues to contribute to the PHP project in numerous forms. He is a frequent lecturer at conferences, the author of php|architect's Guide to Date and Time Programming, and the co-author of PHP 5 Power Programming.