Derick Rethans is a PHP internals expert and author of Xdebug. He works as an independent contractor and consultant on PHP extensions and related projects.
He has contributed to the PHP project in numerous forms (Date/Time Extension, Xdebug, PHP 4.4/7.4 Release Manager). 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. Derick is also the host of the weekly-ish PHP Internals News podcast.